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1. as 5 Noninsulated ring terminal 7 O Insulated ring terminal E m m e _ P Noninsulated quick disconnects Noninsulated spade terminal I F Insulated quick disconnects o Insulated spade terminal C a Fully insulated quick disconnects iii mae Butt connector Fig 60 There are different terminals for different gauges of wire Normally one size terminal will do 10 12 gauge wire the next size is for 14 16 gauge wire and the smaller crimp on terminals will do 18 22 gauge wire It is important to get a terminal with the correct barrel wire crimp area for the wire size that is used It is also important to use a terminal with the correct size of terminal connection Do not use a ring terminal for a 34 inch stud or bolt when a 10 bolt or stud is used Do not try to drill ring terminals to a larger size This will weaken the terminal and lower the current capacity of the terminal It is acceptable to crimp more than one wire into a solderless terminal but only if the barrel of the terminal is large enough to accept more than one wire Shrink tube is available in different sizes and with or without some type of sealing glue Make sure the correct size of shrink tube is used when necessary Too large a size may not shrink down enough to protect the connection Too small a size may shrink too much and split This also will
2. See the chart on the next page for a list of all previous and present day small and large valves for replacement information The 2 1 4 round solenoid valve was developed to replace the AP5564 hex valve The original large round valve had 1 wire and a Tee Handle for a manual valve release This valve has undergone several changes to evolve into the present day 2 wire round valve with a valve release cam lever for manual operation Before the cam release lever valves went from the Tee Handle to a 1 4 valve release nut The present day 12 volt valve as of May 2011 replaces all previous large 12 volt valves except the AP3572 the AP5506 and the AP47151 a present day hi flow valve An adapter wire is needed when replacing older 1 wire valves The large valves have mainly been used on leveling systems but were also used on early room extension systems The large valve is also available as a 24 volt valve The small round valve was developed in the late 1990 s to be used for room extensions These valves were eventually used in leveling systems with smaller capacity jacks The small valve has been produced with and without a screen around the seat of the valve The original valve was equipped with a 1 4 valve release nut for manual operation of the valve The present day valve as of April 2011 has no screen and is equipped with a valve release cam lever The small valve is available as a 12 or 24 volt valve the present
3. 3 Two Wire Switch Non Central Grounded System LIGHT PLATE WARNING LIGHT HARNESS SIGNAL WIRE t Mit One Wire Switch Non Central Grounded System LIGHT PLATE WARNING LIGHT HARNESS ee ss SIGNAL WIRE pF de 9 pa Sis oy eee ee f Fig 17 ie esl On newer systems since about 1994 the warning switches are centrally grounded at one main location with the rest of the grounds needed for the system both for manual and computerized automatic systems On older kick down jack systems and single wire switches for straight acting and fixed jacks the grounds for the switches are dependent on the jack mounting and or the pivot point of the jack Warning switch repair on an older system may involve cleaning the warning switch ground wire connection to the frame or jack bracket or the addition of a ground wire to the cylinder for one wire switches Warning switches have only two positions If the jack is retracted the switch contacts should be open and the warning light for that jack should be off If a kick down jack is vertical or a straight acting fixed jack is extended slightly 1 4 to 2 inches depending on the jack and typed of switch the switch contacts should be closed and the warning light for that jack should be on 2 8 3 1 If a jack is retracted and the warning indicators will not go out just unplug the switch or separate the harness from th
4. GROUND WIRE m 82 ee te p __ 31 JACK PRESSURE SWITCH Fig 19 2 8 4 1 3 wire warning switch diagnostics The basic diagnostics for a 3 wire warning switch is the same as other warning switches The function of the switch is to have open contacts so the warning light is off or have the contacts closed to turn the warning light on If a jack is retracted and the warning light for that jack remains on unplug the pressure switch from the warning switch If the warning light goes out the pressure switch is stuck on If the warning light remains on unplug the switch from the harness If the warning light goes out the problem is the warning switch or possibly the magnet with a straight acting style jack If the light does not go out the signal wire or the B side in a two pin plug in the harness is shorted to ground or there is a problem with the touch panel or control box If a warning light will not come on when a jack is extended or vertical unplug the harness and ground the signal wire B side of a two pin plug If the warning light comes on the problem is the warning switch or the grounding of the warning switch If the warning light does not come on the problem is the wire in the harness connections the touch panel or the control box Some straight acting jacks used with the 610 series non central grounded system used the single wire side port or 2 inch plunger warning switches A special adaptor with resistors built in is used w
5. Diagnosing the AP3572 hydraulic solenoid valve with the transistor This valve is only used for the 400 series leveling systems The control panel for this system was equipped with four paddle switches for manual control of the valves Treat the valve like a single wire valve While pushing the appropriate paddle switch to RETRACT check the voltage between the 12 volt side of the valve and the body of the valve If there is a minimum of 8 5 volts the valve should operate If it does not the valve is bad If the valve will not close unplug the valve If the valve does not close the valve is bad If the valve does close remove the colored wire not the red wire from the harness plug Plug the valve back in If the valve opens the transistor is bad and the valve should be replaced If the valve does not open the problem is in the controls A quick check that you can make to see if the transistor is bad is to simply touch the valve If the valve is scalding hot the valve is bad This test will only work if the control panel has been turned on for a few minutes 30 2 12 PUMP MOTORS The pump motor is the electrical component that creates the flow of fluid in the hydraulic systems The motor is attached to the gears of the pump When the motor turns the gears of the pump turn This creates hydraulic flow The basic parts of the motor are the armature and commutator the poles and field windings and the brushes I don t want to get in
6. I hope this has been informative and helpful Remember this school is based on information pertaining to equipment and diagnostics that is used by HWH Corporation The following is a test that will cover a little of everything that was discussed in this school Down load the test and email it to school hwh com we will correct it and send it back to you We appreciate any input that will help make this and other online HWH schools better If you find mistakes feel free to let us know so we can correct it 58
7. NOTE As of Nov 2010 2000 series control boxes and all potted electronic sensing units have an adjustment enhancement that allows for a more precise level sensor adjustment See adjustment sheets ML47509 control boxes and ML47508 potted sensing unit for detailed use of the adjustment enhancements 2 13 2 Sensing unit programming The electronic level sensing units that are installed in the control boxes have to be programmed to recognize the front of the vehicle and the type of suspension spring or air Sensing units set up for specific applications are programmed at the time of manufacture This is done with the use of resistors placed where the programming pins would be on a programmable sensing unit Control boxes with a re programmed sensing unit must be installed in a specific direction The program chip on the sensing unit board will have a sticker that says THIS SIDE UP and an arrow pointing to FRONT We also refer to the direction of the vehicle No mater what the actual direction the vehicle is pointing we always refer to the front of the vehicle as North The rear of the vehicle is South The passenger side of the vehicle is East The driver side of the vehicle is West NON PROGRAMMABLE SENSING UNIT PROGRA MMING RESISTOR Fig 31 There are four jumpers on the programmable level sensor board which are labeled JP1 JP2 JP3 and JP4 JP1 and JP2 are used for p
8. Self stripping style MTA connectors The self stripping MTA connector has an insulating cover that snaps over the wire insertion area This cover must be removed first When the wire is pushed into the MTA connector it is pushed by two small latches that hold the wire into the connector To remove the wire you must pull the wire by these two latches It is best to try to roll the wire out of the connector Do not jerk the wire from the connector this may cause the contact to be pulled from the connector If the original wire is to be reinserted into the connector approximately 3 8 of an inch of wire should be removed from the wire first WIRE WIRE LATCHES INSULATING cover 111 1 WIRE WIRE Fig 53 46 Crimp style MTA connectors The contact for the crimp style MTA connector has a locking lance to latch the contact into the connector housing Use a small 050 blade screwdriver to depress the locking lance then gently pull the wire contact assembly from the housing If reinserting the original contact back into the housing use the screwdriver to lift the locking lance slightly This will help the lance to catch on the housing when reinserted DEPRESS LOCKING LANCE zi MTA CONTACT LOCKING LANCE ia LOCKING LANCE ACCESS Fig 54 Wire and contact assembly for the crim
9. One connector we do not approve of is the Scotch Lock type connector When two or more wires are spliced together the approved method is to solder and shrink tube the splice Most crimp on terminals are available with insulated or non insulated wire crimp areas Quick disconnect terminals are available fully insulated both the wire crimp area and the terminal connection area Many terminals including butt connectors are now available with some type of shrink tube that protects the wire crimp from moisture and corrosion When using these terminals it 15 important to contact the manufacturer to obtain crimping and heating information for the assembly of the wire and terminal Some of these terminals need to be assembled with a specific tool to eliminate damage to the terminal during assembly It is important to understand that insulated terminals are NOT weather tight The wire crimp must be protected from corrosion if the connector is used in a harsh or wet environment When using a solder less terminal in a wet environment it is best to use a non insulated terminal and cover the wire crimp with a glue filled shrink tube Make sure the shrink tube covers the end of the crimp as well as any bare wire If the end of the crimp 15 not covered the wire crimp will still corrode ruining the connection
10. There are two main things that you have to pay attention to while reading the meter First is any letters words or symbols on the screen after you select a function and when you take a reading This tells you the function and range the meter is operating in The second thing is where the decimal point is Most meters will have multiple ranges Each range starts at 0 the screen might show 0 00 but that is still 0 and will have a maximum Using the Auto Range feature if the meter is so equipped is usually the easiest The meter will automatically pick the range not function that is needed You just note the position of the decimal point and the letter indicating the range to get the correct reading Some meters have a range maximum in multiples of 2 3 or 4 For example a meter with a multiplier of 4 would have the following ranges when the dial is set to Q 4009 0 0 400 ohms 400 ohms is the maximum reading for this range 4KQ 0to4 000 ohms 4 000 ohms is the maximum reading for this range 40 KQ 0 to 40 000 ohms 40 000 ohms is the maximum reading for this range 400 KQ 0 to 400 000 ohms 400 000 ohms is the maximum reading for this range 4MQ 0 to 4 000 000 ohms 4 000 000 ohms is the maximum reading for this range 40 MQ 0 to 40 000 000 ohms 40 000 000 ohms is the maximum reading for this range If using manual range selection the screen will indicate OL for over limit whenever the range limit is exceeded Some meters may have a different indi
11. off When diagnosing air compressor problems it may be important to obtain the open and close pressures of the air compressor pressure switch Pressure switches are used in the systems for several different reasons A pressure switch can be used as an information switch a limiting or safety switch or can be used as a warning switch The following list is the different switches used in our hydraulic and air systems 2 9 1 Jack pressure switch Jack pressure switches are a single wire switch produced by HWH It is used as an information switch The switch is a normally open switch and completes a ground circuit when the switch contacts close Jack pressure switches for the most part do not have a specific pressure rating The exception to this is a jack pressure switch set at 550 psi This switch has its own part number The switch setting depends on the size of jack and the weight of the vehicle Jack pressure switches are adjustable and may need to be adjusted after installation Switches installed at HWH on larger jacks are set at a higher pressure but the replacement switches except the 550 psi switch are all the same setting 220 psi Jack pressure switches are used to let the system computer know that jack is on the ground Most jack switches are used on computerized leveling systems during the stabilizing part of the leveling procedure On towable units the front jack pressure switches must be on to start an automatic leveling or store procedu
12. 400 series paddle switch automatic leveling systems This system was produced from 1985 until about 1992 The AP3572 valve is operated by switching a ground This valve has a transistor attached to the body of the valve One of the valve wires is 12 volts The other wire is the signal or control wire This wire controls the transistor on the valve When a ground signal is supplied to the transistor the transistor supplies a ground for the coil of the valve Ground for the valve coil is supplied through the body of the valve This requires a good ground for the manifold If the manifold mounting becomes loose or corroded this can cause a weak ground which will result in damaging the valve transistor This would cause the valve to not function at all or to remain on constantly whenever 12 volts is supplied to the valve Until 2003 the large valves had a back emf diode installed in the valve Because the necessary protection for the valves is now in the control box the diode was removed The small valves never had the back emf diode Because this diode is still necessary in older systems all replacement large valves have the diode Back EMF Diode Arrangement for Large Solenoid Valves 12 gt l 18 SOLENOID VALVES Fig 25 Except for the AP3572 valve and a singe wire hex shaped valve with a groove the AP5506 the RAP0642 is the replacement valve for all large valves Some older large valves only
13. A normally open switch NO has contacts that are open in the off position A normally closed switch NC has contacts that are closed in the off position A single pole switch SP controls only one circuit at a time A double pole switch DP controls two circuits at a time The key switch on our room panels can control three circuits at a time 3P A single throw switch ST only has two positions off or on The switch can be normally open or normally closed A double throw switch DT will have several positions The switch could be a two position switch that is on in both positions or it may be a switch that has three positions on off on We use one hybrid switch on the 100 and 110 series 4 lever systems leveling systems with air dump That switch is a double pole switch with single throw contacts but it works as an off on maintained and on momentary switch You will see labeling for standard switches that looks like this SPST single pole single throw SPDT single pole double throw DPST double pole single throw DPDT double pole double throw The symbols that HWH uses in diagrams and schematics for different switches look like this SPST SPST NO een NC Single pole single throw normally open Single pole single throw normally c DPST e e NO es Double pole single throw normally open SPDT DPDT ee ne 1 NO e e oe Single pole double throw normally open Double pol
14. A slot and the signal wire is inserted into the B slot It is important that the wires are inserted into the correct slot Newer switches have a small white wire with a ring terminal The ring terminal goes under the screw that holds the switch onto the jack This wire helps insure the cylinder of the jack is grounded This is important on jacks with pressure switches used for automatic systems The jack cylinder is normally grounded through the pivot bracket but the pivot point of the jack can create a weak ground connection for the cylinder due to dirt or corrosion especially on jacks that may not be operated frequently Older kick down switches are two wire switches but had either no Packard connector or a single pin Packard connector Harness and ground connections were made with butt connectors soldiering or ring terminals Replacement switches are supplied with an adaptor that allows you to connect to the existing harness and properly ground the switch It is not recommended to use butt connectors unless the connection is covered with shrink tube when completed Whatever type of connection is made it needs to be waterproof The ground connection will be a ring terminal and the important thing is to make sure the connection for the ring terminal is to clean metal and the completed connection is protected against corrosion 2 8 2 Straight acting or fixed style jack warning switches The warning switches for straight acting or fixed style jacks indica
15. As I said before not everything in a vehicle may be level to each other It is important that levelness is checked from the same place every time Limit movement in the vehicle when adjusting any sensing unit 34 Adjusting a mercury switch sensing unit is fairly simple and will be explained in one of the following sheets The electronic sensing unit is a little more complicated to adjust properly Pay attention to the tweaking instructions when adjusting an electronic sensing unit It is also important to get the vehicle out of level and level the vehicle with the leveling system according to the yellow level indicators after adjusting the sensing unit This is when the tweaking may take place The following are the adjustment and tolerance sheets for the various styles of sensing units MI9543 Non electronic sensing unit tolerances amp adjustment mercury style sensing units ML47509 Electronic sensing unit tolerances amp adjustment control box mounted ML47508 Remote mounted potted electronic sensing unit tolerances amp adjustment IMPORTANT No matter what point of the vehicle is used as the Level Point to check the repeatability of the sensing unit a level should be placed as close as possible to the mounting area of the sensing unit The flexibility of the vehicle will cause the levelness of the main Level Point to change in different parking areas It is important to explain this to the vehicle operator
16. Fig 34 2 The mating halves will have a locking mechanism or latch to keep the connector from accidently coming apart while in use It is important to make sure the locking mechanism is latched when connecting the two mating halves This insures a good quality solid connection of the contacts and when applicable insures a moisture tight seal It is equally important to understand the locking mechanism and not force the connector apart without unlatching the lock when separating the connectors Forcing the halves apart would probably ruin at least one half of the connector See figures on the next page 38 PACKARD WEATHER TIGHT CONNECTOR LOCKING LATCH me LOCKING CLIP J ae ELM a i Fig 35 3 Mating halves will usually have some type of mating guide or pin arrangement that will not allow the two halves to be connected improperly It is important to note that some connectors can be plugged in backwards or upside down if forced Also where there are multiple connectors of the same type present it is sometimes not possible to use a special pin arrangement or some type of keying pin It is always best to mark connectors before removing them or check wiring diagrams for correct wire and connector arrangements UML CONNECTOR UNIVERSAL MATE N LOCK R oO NON ROUNDED CONNECTOR TOWER AND RECEPTICALS ARE THE MATIN
17. If a bag pressure drops to the switch rating the contacts close which completes a ground circuit to the control system This will turn on warning indicators The other purpose of the air bag pressure switches is to keep the vehicle from twisting during a lower procedure There are other programs but the most common program is this If either front air bag switch is on contacts closed a front lower function will halt or cannot be performed either manually or in the automatic mode If either rear drive axle air bag switch is on contacts closed a rear lower function will halt or cannot be performed Tag axle air bag pressure switches do not inhibit any leveling function and are only used as warning switches Air bag pressure switches do not inhibit any raise function Note When an air bag pressure switch is acting as a warning switch there is a delay in the control system between the time the switch contacts close and the warning indicators come on Air leveling system programming tends to change from time to time For systems produced after 2008 contact HWH Technical Services for currant program information 2 9 7 System air pressure switches The system air pressure switch is a warning switch only used on the drive axle air manifolds They are teed into the air supply fitting at the air manifold from the vehicle air system These switches are normally closed two wire switches Present switches will have a two pin Packard connector Older switch
18. The motors have drain holes but this does not totally eliminate the moisture problem It is a good idea to run the system once in a while 2 13 LEVEL SENSING UNITS HWH has had two basic sensing units over the years The original sensin unit was a disk about 4 in diameter It incorporated an arrangement of mercury switches attached to a plate The present day sensing unit is an electronic level sensor The original mercury style sensing unit is not available anymore but can easily be replaced with the electronic sensing unit Both the original and present day sensing units were are available in different configurations It is important to get the correct sensing unit when replacing one BI AXIS SENSING UNIT NON BI AXIS SENSING UNIT MERCURY STYLE MERCURY STYLE MOUNTING SURFACE Fig 29 32 The mercury sensing unit was produced in many configurations The original ones had four wires with a ground strap attached to the housing of the sensing unit More recent sensing units had five wires one of the wires being the ground wire for the sensing unit As shown in Fig 29 all sensing units had a sticker that said This side up and had an arrow marked Rear It was very important that the sensing unit was mounted properly There were different sensing units for the old 400 series paddle switch systems These sensing units had a shielding wire incorporated into the cable There
19. a little later in this section 4 9 When system air pressure is low usually between 70 and 85 psi depending on the switch the switch contacts are closed and positive voltage transfers through the switch contacts to the contacts of the compressor relay If the compressor relay is on the air compressor will run As the system air pressure increases to somewhere between 90 and 120 psi again depending on the switch the switch contacts open This will eliminate positive voltage from the compressor relay coil and the air compressor relay will turn off The compressor will not run even if the system controls are sending a signal to turn the compressor on 2 9 6 Air bag air pressure switches The air bag pressure switches are on air manifolds used in HWH air leveling systems These switches have all been normally closed two wire switches Present switches are a potted switch with a two pin Packard connector The air bag pressure switches are used to complete a ground circuit when the contacts are closed There are different arrangements of air bag pressure switches but the most common is one switch for each side of the front axle or suspension one switch for each side of the drive axle Different ratings of the air bag pressure switches are used 20 There are 10 psi 20 psi and 35 psi air bag pressure switches And there may be a combination of these used on the same vehicle These switches have dual functions First they are used as a warning switch
20. approximately 5 volts When checked in the reverse bias the meter should read OL or open FORWARD BIAS CHECK ig 512 NOTE Some DIODE SYMBOL a t styles of diodes __ gt 12 RED x BLACK when checked CURRENT FLOW VOLTS l p gt in the forward gm REVERSE BIAS CHECK bias mode will DIODE got read a different power for the circuit or voltage g must be off to use E a X the diode check ToT BLACK RED Meter could be ye damaged if power is on Fig 9 If the reading in both directions is OL the diode is open It the reading in both directions is 0 00 the diode is shorted If there is a diode in a harness wire a continuity check of that wire cannot be performed 7 2 6 TRANSISTORS are electronic relays or switches They are used to control the flow of current in a circuit It will either allow the current to flow or stop the flow of current There are three parts to a transistor the base the emitter and the collector There are two types of transistors but we are not going to discuss the construction or do an in depth study of the theory of how the transistor works Except for an old style solenoid valve transistors are used exclusively at the board level of our components I can think of no time at the present that you would have to do diagnostics that directly involve
21. be no ground on the signal wire of the switch When the room becomes completely retracted the magnet should line up with the switch The contacts of the switch should close and there should be a ground on the signal wire of the switch Example 2 The mechanical switch on an automatic travel clamp is a normally closed switch With the travel clamp completely retracted the switch is activated and the contacts should be open When the clamp has extended slightly the switch contacts should be closed Because of the nature of this circuit that involves some diodes the switch should be tested with the wires to the switch unplugged This switch completes a ground circuit when the clamp is extending and a positive voltage circuit when the clamp is retracting Because of the diode in the circuit when extending the clamp there would be a ground on both sides of the switch even with the clamp fully retracted Hall Effect limit switches The Hall Effect switch is a solid state electronic switch that reacts to a magnetic field The Hall Effect switch is used as a room position switch The switch we use acts as a normally open switch that completes a ground circuit The switch has three wires a positive voltage wire a ground wire and a signal wire These switches all use a 3 pin Packard connector The pins of the connector are labeled A B and C A is the ground wire B is the voltage for the switch C is the signal wire Most if not all controls will have i
22. be used where water or moisture is not a concern MTA connectors can be plugged in backwards relatively easy and although a keying pin can be used to assure the connector is plugged in properly not all MTA connectors will use a key pin It is also easy to plug in an MTA connector off one or more pins in either direction when a key pin is not used It is important to use connection diagrams and make a close visual inspection of the connection to prevent connection problems CRIMP STYLE MTA SELF STRIPING STYLE MTA Fig 51 7 MTA connectors are available as two mating halves the plug and the receiver but the MTA connectors are not normally used this way The MTA plug is normally used to attach a harness or a sensing unit to a control box or control panel pin header that is soldiered to a pc board MTA connectors have a locking mechanism to keep the plug from coming loose When the connector attaches to a pin header the lock is a friction style latch If the MTA plug is used with a receiver there is a latch that has to be pushed down to separate the two mating halves When separating the two mating halves or removing an MTA connector from a pc board header do not pull on the wires MTA PC BOARD HEADER PC BOARD CRIMP STYLE MTA CONTACT PIN 1 a NS Fig 52 Wire or contact removal from MTA connectors
23. contact the tube compresses the locking lances allowing the contact and wire to be removed from the housing To remove the wire and contact first the wire cover protector must be opened There is a small locking tab on each side of the cover The sides of the cover must be lifted over the tabs Gently push and hold the wire and contact assembly into the housing Slide the removal tool over the contact until it bottoms out Hold the tool tight against the housing and pull the wire assembly from the housing LOCKING X IRE REMOVAL TOOL AICM COVER E N v PROTECTOR CABLE LOCKING CABLE SEAL 1 SEAL Wire and contact assembly for Packard connectors can be done with a special crimping tool that is available or with a standard terminal applicator designed for crimping Packard contacts The Packard contacts and wires are assembled with two crimps One crimp is for the bare wire connection the second crimp is for the wire seal The special tool does both crimps at the same time A standard terminal applicator requires making two separate crimps The special tool is available from HWH There are different cable seals for different sizes of wire Green 18 to 20 gauge wire Gray 14 to 16 gauge wire Blue 10 to 12 gauge wire The following are the steps for assembling the wire to the Packard contact using a standard terminal applicator 1 Select the proper size seal and slide the seal onto the wire before stripping the insulation This
24. continuous duty and an intermittent duty relay The continuous duty relay is only used with automatic computerized systems This relay is called the master relay Systems that do not use a hydraulic pump may have a master relay It may be mounted in a control box or remote from the control box System diagrams or schematics will supply this information The intermittent duty relay is called the pump relay and is used with any system that has a hydraulic pump motor The relay used on air compressor assemblies is a continuous duty relay All three of these relays have normally open contacts The coil of all pump and air compressor relays is controlled with a signal except for the pump relay on 400 series leveling systems and 200 series Joystick leveling systems A switched ground controls these relays Safety and other relays may be controlled by either a voltage or ground signal You should always check system diagrams and or schematics to determine the control signal for a relay We use a small Bosch relay as a safety switch with all four cylinder and other pressure sensitive room extension mechanisms This relay is normally mounted on the pump motor The Bosch relay can be wired as a normally open or normally closed relay Check specific system wiring diagrams for use and orientation of the relay contacts 2 3 1 Relay diagnostics Before doing the actual diagnostics it is important to know a few things about the relay and the circuit it is in Are y
25. extensions or other type of slide out systems We use room in and or room out limit switches floor up floor down limit switches lock unlock limit switches and clamp retracted limit switches for our electric travel clamps We also use a vacuum switch on some air seal vacuum manifolds Limit switches are used to supply the system controls with information about the position of the equipment the switch is used for This information is critical not only for the proper operation of a room or slide mechanism but also to prevent damage to the mechanism Having a locking mechanism extend while a slide mechanism is moving will create an obvious problem 22 HWH uses several types of limit switches We use several styles of simple magnetic switches We use the electronic Hall Effect switch This switch is also activated with a magnetic field We also use several different mechanical switches The following are our presently used limit switches and their most common use MAGNETIC ROOM POSITION SWITCH NORMALLY OPEN CONTACTS MAGNETIC PREVOST ROOM LOCK POSITION SWITCHES NORMALLY OPEN CONTACTS LOCK LOCK UNLOCK UNLOCK MAGNETIC STANDARD ROOM LOCK POSITION SWITCHES NORMALLY OPEN CONTACTS OLD STYLE NEW STYLE UNLOCK LOCK UNLOCK Lock 3 W
26. had one wire and were internally grounded An adaptor is available to upgrade to the new valve In production at HWH some small valves had a filter screen around the seat and some did not It is a good idea to make sure the screen or the band that keeps the screen in place does not remain in the manifold when the existing valve is removed At the present time all production and replacement valves are manufactured without the screen 27 The following are the different hydraulic solenoid valves AP3572 j T AP5506 ale L AP5564 This valve is on used on the This valve is on used on the 400 series automatic leveling 510 series leveling system system This valve must be This valve has no manual replaced with a like valve release This valve has no manual aan ee release This is the stabilize valve for 510 series leveling systems This valve must be replaced with a like valve This valve has no manual release Large 2 1 4 Round Valves m B gt 20 1 a mi Small 1 1 2 Round Valves
27. halves We refer to the halves as the plug and the receiver The Deutsch connectors are available in several different shapes with various wire size and contact capabilities The Deutsch connectors we use at this time all use the same pins or sockets There is a pin or socket for 12 gauge wires a pin or socket for 14 and 16 gauge wires and a pin or socket for 18 and 20 gauge wires The pins and sockets have a latching shoulder and the mating halves have latching fingers to hold the contacts in place The mating halves of the connector have keys and keyways of different sizes so the connector cannot be plugged in incorrectly The mating halves also have a latching mechanism to keep the connector from coming apart There is a key pin available so like connectors cannot be plugged in to the wrong mating half There is also a cavity seal that must be installed in any wire seal holes that are not used so the water tight integrity of the connector is maintained Round Deutsch connector The round Deutsch connector has a capability of 31 wires The wire size can vary from 20 gauge to 14 gauge wire The mating halves have keys and keyways to assure proper connection One mating half has a locking ring to lock the mating halves together The locking ring also pulls the connector together as it is turned This Deutsch connector requires a special tool for the removal of the wires and pins The numbering for wire placement with this connector is a little different Th
28. helps prevent the wire strands from being separated 2 Strip inch of insulation from the wire 3 Position the wire crimp barrel in the crimping tool and close the handles just enough to hold the contact in place Make sure the crimp wings are centered 4 Insert the bare wire into the wire crimp barrel of the contact and squeeze the handles together Remove the contact from the crimp tool and gently try to pull the wire from the contact to check the crimp 5 Reposition the contact in the crimp tool with the seal crimp wings centered in the crimp tool Make sure the small part of the wire seal is positioned in the seal crimp wings and pull the handles together Do not try to pull the seal from the crimp just make a visual inspection to make sure the seal is crimped to the contact WIRE COVER PROTECTOR Fig 45 Using the special Packard crimp tool is the same basic procedure as above except the bare wire and wire seal need to be positioned at the same time because the tool makes both crimps at once When using the special tool pull the handles together until they release This assures a proper crimp and releases the contact SEAL CRIMP WINGS ASSEMBLED SOCKET WIRE SEAL 8 BARE WIRE CRIMP RINGS WIRE AND WIRE SEAL pP SOCKET Fig 46 43 STANDARD TERMINAL APPLICATOR SPECIAL PACKARD CRIMPING TOOL Fig 47 Contact and connector assembly for Packard connectors The wire and contact ass
29. is most likely the issue CONTROL PANEL WARNING WARNING SWITCHES Fig 13 On 325 series long board manually controlled leveling systems and all automatic systems from the 510 series system on there is no good way to diagnose a problem that is isolated to either the touch panel or control box These systems use multi plex communications between the box and touch panel There is no way to use a test light or multi meter to check the communication signals between the box and touch panel The only thing that can be done is to check the cable connecting the two The cable can be checked for continuity from end to end and to make sure no wires are shorted to ground or together Sometimes it will be necessary to try a different touch panel and if that is not the problem then change the control box Another thing that is important to note about control boxes is that normally there are multiple power sources for the control box Usually ignition power is used for the control box itself and there is switched or unswitched battery power into the control box for external loads such as solenoid valves Some systems may have as many as four different power sources Make sure to review these issues before beginning diagnostics 2 8 WARNING SWITCHES jack down indicator switches Both the kick down style and the straight acting or fixed style jacks have a warning switch to indicate the jack is in the vertical position or extended Most warning
30. leveling or room manifolds and some synchronizing cylinders The part number and pressure rating EH of the switch is identified on a part IN tag on the wire of the switch near the Packard connector Fig 21 Important note All one wire hydraulic pressure switches look the same It is important to get the proper switch when replacing a hydraulic pressure switch Pressure switches like other types of switches can be normally open or normally closed A normally open pressure switch will have open contacts with no pressure The contacts will close as the desired pressure is reached Example The 50 psi pressure switch on the hydraulic manifolds has normally open contacts The circuit is open When the pressure in the manifold reaches 50 psi the contacts close which completes the circuit 18 A normally closed pressure switch will have closed contacts with no pressure The contacts will open as the desired pressure is reached Example The 20 psi pressure switch on an air leveling manifold has normally closed contacts The circuit is complete When the air pressure in the manifold is approximately 20 psi the contacts of the switch will open This will create a break in the circuit Pressure switches also have what is called a hysteresis The quick explanation of hysteresis is the pressure the contacts of the switch open and close at is slightly different Example The contacts of a
31. most important thing to remember about control boxes and panels especially the computerized systems is to not let them intimidate you Understand the system components and diagnosing control boxes and panels for the most part will be easy Maybe the most important things to consider when working on one of our systems with a control problem is Which system is it This can be more complicated than diagnosing the problem All of our different systems have a series number but this number is not noted anywhere on control boxes touch panels or light plates As of December of 2010 the different series we have available or were available in the past are 100 110 series independent lever controlled manual leveling system HYD ONLY 200 210 225 series joystick controlled bi axis leveling system HYD ONLY 300 series touch panel controlled computerized leveling system AIR ONLY 310 series touch panel controlled manual bi axis leveling system HYD ONLY 305 325 series short board touch panel controlled manual bi axis leveling system HYD ONLY 325 series long board touch panel controlled manual bi axis leveling system HYD ONLY 400 series paddle switch controlled computerized leveling system independent or bi axis HYD ONLY 500 series touch panel controlled computerized bi axis leveling system with 14 control box AIR amp HYD 510 series touch panel controlled computerized bi axis leveling system HYD ONLY 600 series touch panel controlled com
32. on the meter MQ 1 000 000 or more ohms Most meters will have an auto range function or a manual range function The auto range function will automatically range needed to read the resistance The manual range function is just what it says You pick the range you want to work in The auto range function is what most people usually use This is a diode test a This function is an audible beep indicator for continuity A This is for measuring amps or current either AC or DC Less expensive meters may have a separate selection on the dial for Amps AC and Amps DC The dial may also be marked mA to measure milli amps or thousandths of an amp Maximum measuring capability for most meters is 10 amps uA This is for measuring micro amps or millionths of an amp This may be on more expensive meters 53 3 2 3 Reading the digital multimeter The best thing I can say about learning to read a digital meter is to study the manual that comes with the meter The screen of the meter will give you the information that you need but different meters will have different ways the information is presented For example I have one meter that on the right side of the screen it will indicate VAC Volts AC or VDC Volts DC My other meter a more expensive unit indicates V Volts on the right side of the screen for both AC and DC volts measurements On the left side of the screen it indicates AC for AC volts measurements and nothing for DC volts measurements
33. pin male or female Packard connectors These are useful when dealing with components like warning switches or pressure switches I also have an adaptor that plugs in between the harness and air or hydraulic solenoid valves This adaptor has a positive and negative lead with alligator clips 1 can connect my volt meter to the adaptor to monitor voltage to a valve with the valve plugged in and energized It is also a good idea to have a 6 or 8 foot number 2 battery cable with clamp ends applied This can be used to supply voltage to a pump motor or to supply a ground for the pump motor Whatever you have make sure you have an assorted supply of good test leads and jumper wires or cables No bare wires coat hangers or screwdrivers please HWH has an assortment of jumpers and test leads or test harnesses available to ease diagnostics on HWH equipment Most of these are listed in our parts catalog that can be viewed on line at www hwh com ASSORTED TEST LEADS Multi purpose voltage and ground test pigtail This pigtail will plug in between any component with a 2 pin Packard connector and its harness connection It allows you to check voltage drop Multi purpose switch test pigtail This connector has a black and a gray 2 pin Packard connector This pigtail plugs into the harness not the component Single wire switch test pigtail This connector has a black 1 pin Packard connector This pigtail plugs into
34. style receiver Make sure all plugs are positioned properly before plugging them in Check wiring diagrams if necessary One size connector is used for 14 to 20 gauge wires A larger connector is needed for 12 gauge wires The contacts for these connectors are locked into the connector with a latching finger for each pin After all wires are inserted into the connector a wedge is pushed into the connector to keep the latching fingers in place The mating halves also have a latching mechanism to keep the connectors from coming apart The 4 pin 6 pin and triangular connectors have a single latch The 8 and 12 pin connectors have 2 latches These latches will be on opposing sides Simply depress the latch or latches on the plug side and pull the connectors apart The connectors are labeled on the wire insertion end of the connector The square and rectangular connectors are numbered The triangular connector uses the letters A B and C RECEIVER sy PLUG ei I 2 TESS LATCH WEDGE WEDGE SEAL Fig 41 Wire and pin removal for square rectangular and triangular Deutsch connectors does not necessarily need a special tool although a removal tool is available A small pocket screwdriver with a flat blade of about 1 8 inch wide will work just fine for the plug half of the connector For the receiver side a small screwdriver and a sm
35. switch seal is an o ring so do not over tighten the switch Do not use any type of thread sealant on the threads of the switch 13 2 8 2 3 The two wire magnetic warning switch is the most recent type of warning switch There are two versions of this switch One has a black two pin Packard connector and the other has a gray two pin Packard connector The switch with the gray connector is the only magnetic switch used for production now with all straight acting or fixed style jacks The connectors have keying slots so a switch with a black connector cannot be plugged into a harness with a gray connector Neither can a switch with a gray connector be plugged into a harness with a black connector Other than the connector the switches look the same The difference is the distance the jack will extend before the warning indicators come on The switch with a black connector will allow the jack to extend 1 to 1 1 4 inches before the warning indicators come on The switch with a gray connector will allow the jack to extend 34 to 1 2 inch before the warning indicators come on The magnetic warning switch is a normally closed switch There is a magnet fixed to the top of the rod inside the jack When the jack is retracted the magnet is close to the switch This opens the contacts so there is no ground circuit for the warning indicators As the jack extends the magnet moves away from the switch which allows the contacts to close This provides a ground cir
36. switches are very simple electrically except the switch used for the early 610 series leveling system jacks This was a three wire switch with resistors and will be discussed separately in this section All jack warning switches including the three wire switches simply complete a ground circuit This ground is used to turn on a red jack down indicator light on the control panel along with some type of master warning indicator such as a light or buzzer It is also used to supply jack down information to the computer processor in automatic computerized leveling systems 2 8 1 Kick down style jacks The kick down jack warning switch indicates the jack has swung to the vertical position It does not indicate the foot of the jack has extended or that the foot is on the ground Originally the warning switch was attached to the cylinder of the jack with a band clamp The switch is now screwed to the pivot point of the jack All kick down warning switches except the three wire kick down warning switches are two wire switches The wires coming from the switch point up when the jack is horizontal and point down when the jack is vertical The electrical part of the warning switch is a small canister inside the main body of the switch This canister has a small steel ball inside along with two contacts that attach to the wires of the switch One wire is connected to ground and the other wire goes to the control panel or control box to supply a ground for the warnin
37. the component connector or connection post If necessary use some type of jumper wire to make this possible We have some special adaptors to make this possible 2 Always check voltage between the voltage supply and the ground connection for the component This could be a wire a mounting bolt or a special ground connection such as a ground stud Do not use a separate frame ground for the initial check If the problem is the ground for the component you could get an acceptable voltage reading using a frame ground If the initial reading indicates low voltage then use a known good ground to make a check This will let you know if the ground is the problem 3 You must have the component or a load turned on to check voltage drop Checking voltage with no load will not give a correct reading for the voltage drop across a component Even long runs of wires or diodes in the circuit will not cause a voltage drop if there is no current flowing through the circuit The only way to create a current flow is by having a load on the circuit Using the voltmeter to find an open in a circuit is a simple process and usually has only one issue tracing the circuit through the vehicle You can also do this with a test light I like to start at the voltage source and work my way to the load Measure the voltage to a known ground If possible using the ground source for the circuit is the best You might find the ground is the issue before going too far As you wo
38. the harness not the component 57 3 3 4 Soldering equipment We recommend that when wires need to be spliced and some type of connector is not used the splice is accomplished by soldering the wires together Butt connectors should rarely be used and are not as reliable as soldering If the right equipment and solder is available soldering does not take much more time than crimping some type of connector If you are repairing a pin type connection we do not recommend soldering Fix the connection with a like connector Several basic types of soldering tools are available There is the soldering gun stylus type electric soldering irons and the butane powered soldering irons Among these are many brands styles and price ranges I like the butane irons They are totally portable and the tips heat very rapidly Most butane kits also come with attachments that will heat the shrink tube that should be used over every solder splice You only need the one kit to do the job After selecting a soldering tool you need the correct solder A small diameter flux core solder is the easiest to work with We use a 032 diameter flux core solder Do not use an acid core solder on electronics The acid core solder will create a corrosive effect A soldering technique is something you have to develop for yourself Practice with the soldering tool you choose so you are used to it when the time comes for an actual repair Here are some soldering tips 1 Giv
39. the contacts to open If the relay suddenly starts to function properly after being tapped it was probably stuck contacts in which case the relay should be replaced Normally closed NC relay diagnostics Diagnosing a normally closed relay is much the same as diagnosing the normally open relay You just are looking for some different answers as you perform the tests When diagnosing a relay that will not turn on open the contacts you start by turning the relay on to perform the tests 1 Is there voltage or ground to the supply input side of the relay 2 Is there voltage to one of the coil terminals of the relay 3 Is there ground to the other coil terminal of the relay 4 Is there voltage to the output side of the relay BOSCH PRESSURE RELAY NC PUMP RELAY SWITCH TPUT OUTPU J iL F 3 SOURCE 3 2 65 rary COIL GROUND 1 1 COIL INPUT L PUMP VOLTAGE gt 1 AND ii 3 12 NTROL 2 SOURCE a VOLTS Fig 7 Check 1 If the answer to 1 is no there is no voltage or ground to the supply side of the relay check its source If the answer to 1 is yes check 2 then 3 If the answer to either is no check the source for that terminal If 2 and 3 are answered yes check 4 Here is the difference between a normally open and normally closed relay If the answer to 4 is yes the relay is b
40. were also many different cable lengths in each style of sensing unit The cable for the sensing unit and the sensing unit head were assembled as one piece and were always replaced as one piece POTTED SENSING UNIT NON POTTED SENSING UNIT ELECTRONIC STYLE ELECTRONIC STYLE MOUNTING SURFACE ae 10 MOUNTING LST PLATE Ck FRONT oe m LA q 2 5 5 1 J o o CI Fig 30 The electronic sensing unit like the mercury sensing unit is produced in different configurations just not as many The non potted electronic sensing unit is used in most touch panel controlled leveling systems The sensing unit is located in the control box Although this eliminates the mounting of a remote sensing unit it does require that the control box or the power unit control assembly be mounted securely to the vehicle Bracing needs to be used when necessary to eliminate vibrations or shaking of the power unit or control box It is also necessary that the equipment housing the sensing unit is mounted as parallel or perpendicular to the frame of the vehicle as possible The sensing unit then needs to be programmed to determine the front of the vehicle and the type of suspension air or spring The non potted sensing unit can be programmed at HWH or is av
41. will have a dial to zero out your multimeter The multimeter has to be set to the mV scale on the selector dial Then you clamp the amp meter around the cable supplying voltage to the pump motor With the pump motor running read the number on the multimeter screen You may want to take a voltage reading at the same time 3 3 2 Wire strippers There are many different types of wire strippers available Sometimes a crimping tool will have wire stripping capabilities The automatic wire strippers are my favorite I suggest a stripping tool with multiple wire gauge holes that are labeled When the wire is inserted into the proper hole and the handles are pulled the wire insulation is cut to the correct depth and then the wire is pulled to remove the cut piece of insulation Just make sure you use a good stripper no teeth knives wire cutters or nail clippers 5 3 3 Test leads Like everything else test leads come in all sizes shapes and forms The main thing to remember about a test lead is it is just a wire so it needs to be sized properly so it does not add to the circuit problem This is especially important when using the lead as a jumper to run a piece of equipment I have several different leads I use I have a fairly long lead with a 12 gauge wire I have another similar lead that has an automotive style fuse holder Both of these leads have alligator clips on both ends I have several different leads in a smaller gauge wire that have one or two
42. 20 psi air pressure switch close at 20 psi The pressure the contacts open at is slightly less approximately 18 psi In most cases the hysteresis of the switch is not important for diagnostic purposes The pressure differences we deal with in the systems are great enough that the hysteresis of the switch will not be noticeable The contacts of normally open switches will close on a rise in pressure Example The 3000 psi hydraulic manifold pressure switch contacts will close as the pressure increases to 3000 psi The contacts of normally closed switches will close on a fall in pressure Example The contacts of the 20 psi air manifold pressure switch will close when the pressure drops to 20 psi The only pressure switch that the hysteresis of the switch is important enough to note on diagrams or when performing diagnostics is the air pressure switches used on air compressors for our air leveling systems There are several types of pressure switches that are used and several different amounts of hysteresis in the switches The contacts of an air compressor pressure switch will close as the pressure drops to a certain level The contacts will open as the pressure increases to the desired level Example On the APO198 air compressor the pressure switch contacts will close when the pressure drops to 70 psi This will turn the air compressor on If needed The contacts of the switch will open when the pressure rises to 90 psi This will turn the air compressor
43. ASE NUT WITH SCREEN RAP90729 OBSOLETE a 24 VOLT VALVE WITH 1 4 RELEASE NUT RAP91882 AP36234 24 VOLT VALVE WITH RELEASE CAM RAP91882 AP41040 12 VOLT VALVE WITH RELEASE CAM HI FLOW RAP92108 AP42632 12 VOLT VALVE WITH RELEASE CAM NO SCREEN RAP90729 Sern a 12 VOLT VALVE WITH RELEASE CAM NO SCREEN RAP90729 29 2 11 3 Solenoid valve diagnostics All solenoid valves used by HWH air and hydraulic are tested the same way for electrical problems The only exception is the AP3572 hydraulic valve with the transistor We will discuss that valve a little later in this section The two main questions that need to be answered before diagnosing the issue are What is the operating voltage of the valve Is the valve a normally closed or normally open valve To diagnose a valve that seems to be energized all the time you simply unplug the valve If a normally closed valve remains open allowing fluid or air to flow the valve is bad If a normally open valve will not allow fluid or air to flow the valve is bad If when unplugged the valve returns to its normally off position the problem is the controls When diagnosing a valve that will not energize there are several things that can be done The recommended way to diagnose this type of problem with HWH systems is to check the voltage for the valve When making this test the valve must be plugged in and turned on The leads for the voltmeter must be connected to the power an
44. Customer Support amp Technical Service There is a HWH Control Box quick reference guide in the parts catalog It is also very important to get the correct part number when ordering repair parts There are different control boxes touch panels or light plates in every series of leveling system The 2000 series CAN system has over 150 different control box numbers There are 8 different light plates for the 200 210 225 joystick leveling systems The differences could be kick down or straight acting jacks spring or air suspension how many room extensions the vehicle has or a variety of other reasons Different controls are used for motorized or towable units rooms with locks or travel clamps or maybe the vehicle has air leveling with or without a tag axle Whichever series the system is it is important to make sure the correct controls are used It is also important to note that sometimes we use a generic type control box that will replace several different control boxes If the replacement box does not have the same number as the original it could be a good idea to check and make sure it is the correct box Just because two control boxes touch panels or light plates looks the same it doesn t mean they are the same 310 series 4 jacks w air dump 310 series 3 jacks w air dump 325 series 4 jacks w air dump AP10054 AP10353 AP31351 Oo HWH HYDRAULIC LEVELING 6 HWH HYDRAULIC LEVELING 6 HWH HYDRAULIC LEVELI
45. ECTRICAL CONNECTORS AND WIRE TERMINALS This section is one of the more important sections of ELECTRICAL COMPONENTS The reason I say this is that very often connectors are overlooked as the possible weak point of a circuit The purpose of a connector or terminal is to pass current from one set of wires to another or to pass current from a wire to a component terminal The way to view a connection is not to see one connection point but to see each connection point as multiple connections When two wires are jointed through a connector there is not one connection but instead there are three When a wire is attached to a component such as a relay there is not one connection but there are two connections at that point The following examples will show you what I mean 1 CONNECTION POINT 3 CONNECTIONS 1 CONNECTION POINT 2 CONNECTIONS WIRE CONNECTION TO WIRE CONNECTION WIRE TERMINAL CONNECTION PIN CONTACT TO PIN CONTACT TO PUMP RELAY TERMINAL SOCKET L i y WIRE CONNECTION PIN CONTACT TO WIRE TERMINAL CONNECTION TO PUMP RELAY PIN CONTACT SOCKET Fig 33 37 There are several reasons a connector can be a weak point in a circuit There may be corrosion or some other type of contaminant on the pins of a connector Even water tight connectors can be susceptible to this problem The pins may not fit tight together causing a loose connection more resistance in the c
46. ELECTRONICS amp HWH 120CT12 1 PREFACE This section deals with electronic equipment and components We will discuss common electronic components and components that are specific to HWH The discussion will include identification of the components how these components function and diagnostic information needed for testing In the component section we will discuss most of the different electrical connectors that are used by HWH This will help you identify the connector along with an explanation of how to assemble and remove wires and or pins from the connectors We will also discuss the correct tools needed to work on these connectors There is also a section on test and repair equipment This section describes some basic equipment needed to diagnose and repair HWH systems The discussion includes choosing equipment and the function and correct use of this equipment 2 ELECTRICAL COMPONENTS 2 1 MANUAL CONTROL SWITCHES Manual switches come in many styles and many different contact actions We use toggle switches rocker switches push button switches and key switches The terminology used to describe the contact actions is important to understand A momentary switch is a switch that will return to its original position when released You have to push and hold the switch to keep it activated A maintained switch is a switch that will remain in the position it is pushed to This type of switch has to be pushed to return it to its original position
47. G is GUIDE P Aol OX Fig 36 4 Most connectors have pins and sockets that can be remove and replaced if necessary This is true of most of our connectors The only connector we use that does not have replaceable pins and sockets is one of the MTA connectors we use We use two styles of MTA connectors one has replaceable pins sockets and the other does not Some of the connectors we use need a special tool for pin removal It is important to use the correct tool to eliminate damage to the pin or socket There are also special tools for crimping the wires to the contacts Sometimes the special tool is the only tool that will do a proper crimp PACKARD CONNECTOR CRIMPING TOOL PACKARD PIN SOCKET REMOVAL TOOL Fig 37 5 The contact pins and sockets will have some type of latching mechanism to make sure the contact will not push or pull out of the connector If the contact is not seated properly into the connector the contact can be pushed out when the mating halves are assembled or could be pulled out inadvertently if the wire is pulled on This can create an open or weak connection Even worse this very often will be an intermittent problem It is a good idea to pull gently on the wire after inserting the contact into the connector This will insure the wire is crimped properly and that th
48. IRE HALL EFFECT ROOM POSITION SWITCH A F lt o SINGLE POLE NORMALLY OPEN OR NORMALLY CLOSED MECHANICAL ROOM POSITION SWITCH MECHANICAL TRAVEL CLAMP POSITION SWITCHES SINGLE POLE DUOBLE POLE WIRED NORMALLY CLOSED ONE SIDE NORMALLY CLOSED ONE SIDE NORMALLY OPEN Fig 23 23 Some limit switches are used to switch positive voltage and others switch ground It is important to check wiring diagrams to determine what type of circuit the switch contacts are completing Many of our room and lock limit switches do switch a positive voltage circuit In the case of a cut or pinched wire a fuse will blow instead of giving the controls a false reading of a completed ground circuit Magnet and or switch positioning is also important so the switch is not made too soon or not made at all 2 10 1 Limit switch diagnostics Before diagnosing limit switches make sure what kind of switch it is along with how and when the switch should function Is the switch a room in or out switch a floor up or down switch or is the switch a lock or unlock switch Is it a magnetic mechanical or Hall Effect switch Should the switch function as a normally open or normally closed switch Although the switches shown above give that information it is important to remember there can always be exceptions to the rule Does the switch complete a ground circuit or a positive voltage circuit When you have this information diagnosing the s
49. NG o A You will notice that the touch panels in Fig 11 all have the exact same lexan cover There is no visible difference at all between the two 310 series panels The only visible difference between any of the panels is that the 325 series panel has a different pc board and plug assembly This difference would not be noticeable unless the panel was removed Even then you have to know what you are looking for Control boxes are even worse You could easily have 10 20 or more boxes with no physical difference but due to programming differences in the computer chip the boxes will have a different part number 2 7 1 Control box or panel diagnostics as I said earlier can be simple I don t mean you will never encounter some system that makes you want to find a new profession All of us even our engineers have been there But I can tell you from experience 90 of the time we discover something simple that was missed because of inaccurate information or over thinking the problem A loose wire corrosion low battery voltage or something else that was overlooked We have even seen a whole day wasted because nobody checked to see if the park brake was set The easiest way to diagnose an electrical problem if you don t understand the system or components is to use the correct repair manual The HWH repair manuals are written in an order that fo
50. The 2 inch plunger switch was also a single wire switch This switch was only used with 24 000 Ib capacity jacks The name of the switch says it all the jack has to extend approximately 2 inches before the warning indicators come on The plunger switch is a normally closed switch The small rod coming from the bottom of the switch opposite end from where the wire attaches is the plunger As the rod extends approximately 2 inches a spring in the switch pushes the plunger out allowing the contacts in the switch to close which completes a circuit for ground from the body of the switch to the wire of the switch This turns on the warning indicators As the rod retracts it pushes the plunger rod up which opens the contacts of the switch in turn opening the ground circuit Like the side port switch the pivot point of a straight acting jack with a plunger switch can be a weak point of the ground circuit due to dirt or corrosion Attaching a small band clamp wire assembly to the switch and directly to the frame can help if this problem arises Allow enough slack in the wire for the jack to pivot without putting a strain on the wire Depending on access issues the replacement of a plunger switch is relatively simple The only requirement is that the jack is fully retracted before removing the switch Unplug the switch and unscrew the switch from the jack cylinder A small amount of oil may come out of the top of the jack Install the new switch and tighten The
51. ad If the answer is no the relay is good As with a normally open relay if the contacts of a normally closed relay will not close remove the control voltage or ground from the relay If the contacts remain open the relay is bad When diagnosing any relay it is important to remember that the wire connections to the relay may be the issue and not the relay Many relays are changed because of a miss diagnosed problem A weak connection can seem to be a bad relay When the relay is replaced the problem is fixed not because the relay is bad but because the connections are fixed when the relay is replaced When diagnosing a relay using the diagnostic procedure discussed above put the probes of the test light or meter on the relay posts not the wire terminals If connections are weak that will show up when testing 2 4 FUSES are an important control device in any electrical system Fuses are use to protect wiring or printed circuit boards from damage or fire Damage of fire is caused by over heating due to excessive current draw because of a faulty component circuit overload or a short A fuse very simply creates a break in the circuit when its current rating is exceeded We have used many different types of fuses over the years We have used automatic circuit breakers automotive glass fuses large blade fuses standard size automotive blade fuses the newer mini blade fuses buss type fuses and poly fuses The circuit breakers and large blade fus
52. ailable as a programmable sensing unit that can be easily programmed in the field The programmable sensing unit is mainly used for aftermarket installations and repairs The potted electronic sensing unit is an electronic sensing unit encased in a plastic housing and sealed with epoxy The potted sensing unit is mounted remotely from the control box light plate or valve Like the original sensing units the potted sensing unit is marked with mounting instructions This Side Up and an arrow marked Front The sensing unit must be mounted per these instructions to function properly Please note the original sensing units had the arrow pointing Rear and the new potted sensing units have the arrow pointing Front The potted sensing units have only a short cable as part of the assembly The cable that connects the sensing unit to the controls is a separate piece of equipment The length of the cable can vary along with the type of connector needed to attach the cable to the controls Because the potted sensing unit is always mounted in one direction it does not have to be programmed for direction It does however need to be programmed for suspension type and leveling format either bi axis or non bi axis leveling The potted sensing unit is not programmable in the field and it is important to get the proper sensing unit for the type of suspension and leveling system the sensing unit is used with 33 All leveling systems at thi
53. all We have used hydraulic pressure switches in the past that were produced by a different manufacturer and the pressure switches we use on air leveling systems are also produced by a different manufacturer The following are some of the pressure switches that have been used or that are still being used by HWH There have been a few other different pressure switches used but these were are the most common All switches used by HWH can be diagnosed the same as these switches Two wire air pressure Two wire air pressure switch used on air switch used on air manifolds and air manifolds and air 2N 5 compressors This switch compressors This switch 8 is no longer used It can is the current switch that is NASON k MODEL SM be replaced with a new being used It is available in several different pressure S ratings style air pressure switch 1 lt Je ale iiH m Adjustable air pressure switch used only on air compressors This switch comes with no wires and is N wired during the assembly O of the air compressor Se One wire hydraulic pressure a N i 1 switch This switch is produced HWH It is used on jacks pressure switch This switch was used primarily on leveling system manifolds The normal setting for this switch is 3000 psi
54. all needle nose plier will work First the wedge must be removed Use the screwdriver to pop the wedge out of the plug or use the pliers to pull the wedge out of the receiver After the wedge is removed use the small screwdriver to hold the latching finger away from the pin While holding the latching finger gently pull the wire out of the connector Si r FINGER PIN gt i LATCHING SHOULDER Fig 42 Wire and pin assembly for Deutsch connectors Crimping of wires into the contacts for the Deutsch connectors is the same for all Deutsch connectors used by HWH at this time We use three different sizes of pins and sockets One size for 18 and 20 gauge wires one size for 14 and 16 gauge wires and one size for 12 gauge wires The pins and sockets for the 14 and 16 gauge wires have a green stripe around the wire receptacle The size difference for the 12 gauge pins and sockets is obvious It requires a special tool to perform the wire crimp for the Deutsch pins and sockets The tool has several adjustments that must be made before crimping a wire into a contact There is a wire size selector and a contact depth adjustment screw 41 The following is the proper procedure for crimping Deutsch connector contacts 1 Strip inch of insulation from the wire 2 Lift and turn the wire size selector to the appropriate wire size 3 Select the correct pin or socket for the gauge of wire us
55. alve may have two ring terminals Other than changing wire ends these valves are totally interchangeable Older systems had harnesses with one wire going to each air leveling valve The ground for the valve was done right at the manifold Adaptor wires are available to adapt valves with two pin connectors to the old single pin harnesses None of our air valve have a back emf diode built into the valve so either wire of any of the air valves can be voltage or ground See section 4 2 Electric coils for an explanation of the back emf diode 25 The following are the seven basic valves Valves on older systems may look slightly different due to a different coil arrangement that was used All of these valves have 12 volt coils AP1940 AIR VALVE l AP25428 HI FLOW AIR VALVE AP31928 HI FLOW AIR VALVE w om AP31930 3 WAY AIR VALVE a gt qe AP4480 AIR VALVE This is a normally closed valve and is activated by switching voltage This valve is the primary valve used on basic air leveling manifolds but is also used on air seal manifolds Valves supplied before the mid 90s had a different coil arrangement This is a normally clos
56. anges or scales on your meter 54 Here are a few problems to practice converting meter readings from one scale to another The answers are at the end of this section 3 2 4 Don t worry about a maximum multiplier or rounding the numbers off These may not be readings you will see on your meter This is just to help you understand how to transpose the numbers 1 42 3 Q KQ 6 625A uA 2 1 73 MQ KQ 7 8 36 V mV 3 236 mV V 8 147 568 mA A 4 639 7 KQ Q 9 22 35 MQ Q 5 36 1 uA mA 10 71mV V F Diode Check Refer to section 2 5 for the correct information on testing diodes The important thing to remember about checking a diode is if the diode is installed on a circuit board or is in a circuit with other components the diode test may not be accurate One of the diode legs needs to be disconnected from the circuit to get accurate test results Audible beep continuity test The beep test is only a basic test for continuity It is not a very accurate test Most meters will beep with up to a hundred ohms of resistance some at a higher level Here are a couple of examples why the beep test is not a reliable test Example 1 A 100 foot piece of 16 gauge wire only has 2525 ohms of resistance The beep test certainly does not tell us that piece of wire in not damaged If the 100 foot piece of 16 gauge wire was cut and is now only equivalent to a 30 gauge wire i
57. at a tech working on generators converters and inverters may need When comparing Digital meters you will hear the term True RMS as a meter feature If you need True RMS Root Mean Square explained you don t need this feature If you are a tech that understands True RMS you probably already have a True RMS meter Please do not take offense to this As a tech working only with HWH equipment I did not know what a True RMS meter was good for nor did I care In fact although I now understand True RMS I still don t care if I am using a True RMS meter I only bring up the subject to help you decide on a meter Don t spend money you don t need to You can always upgrade someday if necessary 52 Another choice is between a digital or analog meter The digital meter is by far the most popular among service techs The digital meter is easier to read and less awkward to use than most analog meters My preference is a digital meter BUT there is one advantage to an analog meter If you are looking for a voltage spike or dip a digital meter may not react quick enough to catch the spike or dip The needle of the analog meter will react to the spike or dip This could be a useful feature but I still recommend a digital meter It just may be helpful to know where to get your hands on an analog meter if you need one These are a few things I would look for in a digital meter 1 Quality 2 Serviceability 3 Auto Range fea
58. be it is easy to create a short to ground when testing a voltage source It is a good idea to cover all but approximately 1 4 inch of the test light probe with shrink tube to insulate the probe Many newer test lights have this done 5 Make the end of the probe a little dull after purchasing the light This will keep you from piercing the wire insulation with the test light probe 6 Remember a test light assembly is like two large gauge wires with a very small gauge wire connecting the two A test light can and will complete an open circuit that could cause a component to turn on How much of a load a test light could turn on will depend of the test light This can be a useful feature of the test light but could also create a safety issue Know what you are testing so you do not create a hazard 7 Make sure the test light is working Check the light with a known good ground and voltage source 3 1 1 Selecting a test light As was stated earlier you get what you pay for Don t skimp on price when purchasing test equipment Get a good quality reliable test light with a durable cord and insulated alligator clip 1 like a light with a medium length insulated probe and a coiled wire I do not like the LED test lights It is easier to see a difference between bright and dim with a standard bulb There are many different styles with different features such as ground or voltage detection There are also kits available that come with pin adapt
59. cation One of my meters indicates OUCH whenever a range limit is exceeded It is important to understand the range symbols and how to translate the figures M is MEGA MEGA is x 1 000 000 6 4 MQ is 6 400 000 ohms Kis KILO KILO is x 1 000 21 3 KQ is 21 300 ohms m is milli milli is 001 or 1 1000 329 mA is 329 amps u 15 micro micro is 000001 or 1 1 000 000 6 729 uA is 006729 amps The symbol M ohms volts amps moves the decimal point 6 spaces to the right to convert to ohms volts or amps The symbol K ohms volts amps moves the decimal point 3 spaces to the right to convert to ohms volts or amps The symbol m ohms volts amps moves the decimal point 3 spaces to the left to convert to ohms volts or amps The symbol p ohms volts amps moves the decimal point 6 spaces to the left to convert to ohms volts or amps The following example is what a meter with a maximum multiplier of 4 would read when measuring a circuit with 36 178 ohms of resistance when using the manual mode in all the Q ranges 400 Q OL 4 KQ OL 40 KQ 36 18 KQ 400 KQ 36 2 KQ 4 MQ 036 MQ 40 MQ 04 MQ In the AUTO mode the meter will automatically go to the smallest range the read the resistance The AUTO range would go to the 40 KQ range and read 36 18 KQ Some meters just use a straight reading for each range Q is 0 to 999 KQ is 0 to 999 999 and MQ is 0 to 1 000 000 plus Whether in AUTO or manual mode you must know how to read the r
60. cement of the pins and sockets to assure that different UML connectors with the same number of wires are not plugged in together The connectors are numbered on the wire insertion side for wire placement There is a locating tab to find location of pin 1 There is a special removal tool for the UML contacts This tool should be used to eliminate the chance of damaged contacts or housings There are two crimps for the UML contacts a bare wire crimp and an insulation crimp This can be accomplished with a standard terminal applicator designed to do these crimps The two crimps are done individually with the standard crimp tool There is also a special crimping tool available from HWH that performs both crimps at the same time The special tool is fairly expensive but does a much nicer job than the standard crimp tool 6 PIN UML 6 PIN UML Locking RECEIVER 0 6 Labo cur lt CLIP LATCH LATCH UML UML H OH PIN SOCKET SLEEVE LOCKING LANCE Do j SO 5 12 BARE WIRE QO OJO gt INSULATION CRIMP Fig 48 44 Wire and contact removal for UML connectors The locking lances on the contacts must be compressed to remove the wire and contact fro
61. cle with an air suspension has less bounce while leveling electronic sensing units for vehicles with an air suspension has a slightly tighter tolerance than the standard sensing unit for vehicles with spring suspensions The air suspension sensing unit should not be used on vehicles with spring suspensions The leveling system performance may be diminished Before adjusting a sensing unit it must be determined what level is Level is level when looking at a leveling instrument BUT this is not true when looking at a vehicle especially a motor home If the countertop is level the floor of the vehicle may not be If the floor is level the refrigerator door may swing one way or the other If possible the owner of the vehicle should be consulted before adjusting the sensing unit After determining what should be level and the vehicle is leveled to that object it is a good idea to check several other places on the vehicle to make sure nothing will be to far from level compared to the main leveling point It is also important to pay attention where the main leveling point is If that point is in a room extension the room should be extended with the main point level before adjusting the level sensing unit Level with the room in may not be level with the room out and normally the room will be out when the vehicle is leveled and in use Finally make sure the vehicle owner operator knows where you have checked for the levelness of the vehicle
62. cuit for the warning indicators The harness has two wires for the switch One is the ground supply from the control box or panel the other is the signal wire for the warning light circuit at the control box or panel Where the wires are inserted into the connectors for the harness and the switch the connectors are labeled A and B The ground wire is inserted in the A slot and the signal wire is inserted into the B slot It is important that the wires are inserted into the correct slot Newer switches have a small white wire soldiered to the ground wire of the switch and to the body of the warning switch This wire helps insure the cylinder of the jack is grounded This is important on jacks with pressure switches used for automatic systems The jack cylinder is normally grounded through the pivot bracket but the pivot point of the jack can create a weak ground connection for the cylinder due to dirt or corrosion especially on jacks that may not be operated frequently Replacing an existing warning switch without the small white wire with a new switch will solve a grounding problem on an older jack Replacing a magnetic warning switch requires the jack to be fully retracted Removing a warning switch with a jack extended will cause a considerable mess and could be a hazard if the vehicle is supported by the jack The jack will retract if the switch is removed To replace the switch unplug the switch and unscrew the switch from the jack Install the
63. d ground supply for the valve where the valve plugs into the harness If testing a single wire valve the ground lead of the meter should be held to the body of the valve Do not poke holes in the wires or try to slide the test lead by the connector seal The water tight integrity of the wire or connector will be damaged Use some short test leads to connect the valve to the harness or a testing adaptor is available from HWH for 2 pin Packard Connectors GROUND o qe 12 VOLTAGE VOLTS mj Fig 27 If testing air solenoid valves the valves should energize if there is a minimum of 8 0 volts at the valve 12 volt valves If testing hydraulic solenoid valves valves with either a 12 volt or 24 volt coil should energize with a minimum of 8 5 volts at the valve If you have the minimum voltage required and a valve will not energize the valve is bad It is not necessary to check the resistance of the coil Two wire valves can also be tested with a simple continuity tester There should be continuity very little resistance between the two wires of the valve There should be no continuity an open circuit between either valve wire and the body of the valve If the valve passes these tests the valve should still be tested using the voltage method The continuity tests will only tell you if the valve is bad not if the valve will work
64. day small valve 12 or 24 volt replaces all previous small valves 12 or 24 volt except the AP41040 a hi flow small valve used with step covers Fig 26 28 VALVE REPLACEMENT CHART LARGE 2 1 4 SOLENOID VALVES ORIGINAL REPLACEMENT PART DESCRIPTION PART AP3572 12 VOLT VALVE WITH TRANSISTOR RAP3572 OBSOLETE 12 VOLT 1 WIRE HEX VALVE HI FLOW eae AP5506 REQUIRES RAP91915 ADAPTOR WIRE OBSOLETE 12 VOLT 1 WIRE HEX VALVE NEEDS ADAPTOR WIRE ERY AP5564 REQUIRES RAP91915 ADAPTOR WIRE OBSOLETE 12 1 OR 2 WIRE VALVE WITH DIODE AND TEE HANDLE 1 WIRE RAPOS42 AP0642 VALVE REPLACEMENT REQUIRES RAP91915 ADAPTOR WIRE AP31628 12 VOLT 2 WIRE VALVE WITH RELEASE CAM NO DIODE RAP0642 OBSOLETE 12 VOLT 2 WIRE VALVE WITH 14 RELEASE NUT NO Kees AP32629 DOIDE AP36232 24 VOLT 2 WIRE VALVE WITH RELEASE CAM RAP91883 12 VOLT 2 WIRE VALVE WITH RELEASE CAM WITH 559872 DIODE OBSOLETE eee 12 VOLT 2 WIRE VALVE WITH RELEASE CAM RAP0642 47151 12 VOLT 2 WIRE VALVE WITH RELEASE CAM HI FLOW RAP92824 apago 12 VOLT 2 WIRE VALVE WITH REMOVABLE RELEASE CAM aera NO DIODE AP51111 12 VOLT 2 WIRE WITH REMOVABLE RELEASE CAM RAP93180 SMALL 1 1 2 SOLENOID VALVES ORIGINAL REPLACEMENT PART DESCRIPTION PART Seine 12 VOLT VALVE WITH 14 RELEASE NUT NO SCREEN RAP90729 gerne 12 VOLT VALVE WITH 1 RELE
65. e 1 Is there voltage or ground to the supply or input side of the relay 2 Is there voltage to one of the coil terminals of the relay 3 Is there ground to the other coil terminal of the relay 4 If 1 2 and 3 are yes is there voltage or ground to the output switched side of the relay 2 SOURCE CONTROL BOX gt COIL VOLTAGE 1 SOURCE 3 SOURCE INPUT 12 VOLTS Fig 6 As always it is a matter of using the process of elimination If the answer to 1 is no there is no voltage or ground to the supply side of the relay check that source If the answer to 1 is yes check 2 then 3 If the answer to 2 or 3 is no check their source If the answer to 2 and 3 is yes go to 4 If the answer to 4 is yes the relay is good If the answer is no there is no voltage or ground on the output side of the relay the relay is bad Diagnosing a normally open relay that is on contacts closed at all times is easy to diagnose All that needs to be done is to remove the control wire or check the control wire for voltage or ground whichever is used to control the relay coil If the control voltage or ground is not present or the control wire is removed and the relay stays on the relay is bad It is important to note that sometimes the relay contacts will open if the relay is tapped It may not take much of a tap to cause
66. e double throw normally Fig 1 Another important thing to note about switches is their current capacity Like wires switches can conduct only so much current without overheating or burning out The current capability of the switch along with the maximum voltage the switch can be used with is usually indicated on the body of the switch It is important that these capacities are not exceeded The contacts of the switch will probably be ruined if its capacity 15 exceeded This is why we use relays that can supply large amounts of current to different loads instead of wiring the load directly to the switch Most of our manual switches are rated for 5 to 10 amps some up to 15 or 20 amps It is important that the correct switches are used to maintain correct operation of our systems Switches also have different types of terminals The terminals can be soldiered such as with a board mounted switch or they can be used with fast on connectors push on or ring terminals screw on Terminals are usually numbered The numbers are used to make assembly and repair diagrams to make sure the switches are wired and assembled properly 2 1 1 Manual switch diagnostics is very simple once the switch action is known Answering a couple of questions will usually diagnose switch problems Will the switch stay where it is supposed to if it is a maintain type switch Will the switch release or does it seem to stick if it is a momentary switch Do the contacts open w
67. e center wire is number and subsequent numbers work out from the center wire in a circular pattern LOCKING WIRE SEAL REMOVAL TOOL GUIDE KEY Fig 40 Wire and pin removal for the round Deutsch connector is accomplished with a special tool This tool must be used so the connector housing is not damaged The tool has a slot for the wire to lay in Then the tool is slid along the wire through the wire seal until you feel the tool bottom out This will spread the latching fingers so the pin can be removed Be careful to not damage the wire seal when inserting the removal tool Gently pull the wire and tool out together Do not force it If the wire will not come out easily reinsert the tool and try it again 40 Square rectangular and triangular Deutsch connectors These Deutsch connectors come in various wire number or size capacities and also in different colors We use 4 6 8 and 12 pin connectors The triangular connector is a 3 wire connector We also use these connectors in gray green black and brown The different color connectors have different keys and keyways so that one color cannot be plugged into a different color It is important to know that the early brown and green 12 pin connectors could be plugged in upside down if pushed hard enough The keying has been changed for these connectors to fix that problem An older male connector can be used with the new receivers but the new male connector will not plug into an old
68. e contact is latched in the connector DEUTSCH CONNECTOR UML CONNECTOR SHOULDER a 7 a PIN LATCHES JH PIN LANCES A 7A SHOULDER Fig 38 39 6 Multiple pin connectors will have pin locations numbered or labeled Connectors may also have a locating tab This tab indicates where pin 1 is This labeling identifies the wire location in the connector for assembly or repair This information is available on harness drawings system schematics and wiring diagrams in repair manuals or many operators manuals is important that correct wire location is maintained Improper system operation or damage to components can occur if correct wire location is not maintained Mark all wire locations before removal Refer to drawings when necessary do not guess or work from memory PACKARD WEATHER UML CONNECTORS TIGHT CONNECTORS DEUTSCH CONNECTORS LOCATING il te TAB w s OO 000 Fig 39 The following are different types of connectors used by HWH 2 14 1 1 Deutsch connectors The Deutsch connector is a water tight connector The connector has a seal where the wires enter the connector and another seal for the two mating
69. e receptacle The contacts can only be inserted into the housings one way They should push in fairly easy Do not force the contact into the housing When the contact is fully inserted into the housing you should hear a click as the contact spring latches snap into place Make sure the wire seal did not pull out of the crimp as the assembly was pushed into the housing Give the wire assembly a gently tug to insure the contact is latched in place Install the wedge You will here a click as the wedge snaps into place Remember the housings have no markings so it is important to pay close attention to wiring diagrams to make sure the wires are all in the proper position 49 2 14 1 6 5010611655 crimp on terminals and quick disconnects There are many types of these terminals available The main terminals we use are ring terminals spade terminals and quick disconnects We sometimes refer to the quick disconnects as fast ons Another common crimp style terminal is the butt connector We do not usually recommend the use of butt connectors It is hard to inspect a butt connector to make sure the wires are properly crimped into the connector Also butt connectors are not weather proof and many times these connectors are used in harsh environment areas If butt connectors are used the finished connection should be protected with a glue filled shrink tube In the few instances we supply a harness with butt connectors we also provide the shrink tube
70. e switch contacts This is important because a component with a diode installed in the component must maintain the proper polarity when it is wired into the circuit This is called a back emf diode If the component is wired in reverse this will ruin the diode because a direct short is created in the component This will create a short in the circuit and blow a fuse or damage wiring or other components Sometimes the diode will be completely destroyed This will allow the component to work but will now have no protection against the voltage spike when the coil is turned off Other components can now be damaged For most components we have protection built into the control circuit Our large valves used to have the diode built into the valve Large replacement valves still have the diode for use in older systems but this same replacement valve is used for repairs in new systems also It is just a good rule of thumb to not change the polarity of the wiring in a system You never know when you may be causing an issue We will show you examples of coils with and without diodes when we discuss other components such as relays next component we discuss or solenoid valves 2 3 RELAYS Relays are electrically controlled switches They are sometimes referred to as solenoids but if it is used as a switch it is a relay Pictured are several relays presently used by HWH In the past HWH has used different styles and brands of relays Some of the older rela
71. e warning switch on older systems and see if the indicators go out If they do the problem is at the switch If the switch in question is a magnetic switch remember there is a magnet in the jack that opens the switch contacts The magnet could be the problem If the indicators don t go out with the switch unplugged the signal wire in the harness is shorted to ground or there is a problem with the light plate control panel or control box For the newer two wire switches with the small ground enhancement wire make sure the ground wire in the switch and harness plug are in the A slot If the wires are reversed in either the switch or harness plug the warning indicators will be on all of the time when the switch is plugged into the harness When the wires are reversed in one of the plugs there is a direct ground on the signal wire as long as the pivot point of the jack has good conductivity to ground Remember the ground enhancement wire on the switch takes care of a weak ground point that may be at the pivot point of the jack If using a meter to check the switch when the jack is retracted the meter should show the switch totally open 15 2 8 3 2 If a kick down jack is in the vertical position or a straight acting fixed jack is slightly extended and the warning indicators are not on again unplug the switch or separate the switch from the harness Locate a good ground point and ground the signal wire in the harness This would be the wire in the B s
72. e will discuss are the test light and the volt meter or multi meter 3 1 TEST LIGHTS There always seems to be a discussion about what is the best piece of equipment to use when testing electrical equipment Many instructors I have talked to and many books I have read refuse to even give the test light a passing mention about its value One instructor I knew made his students throw their test lights away when they started the school The test light is a valuable piece of test equipment It is certainly true that a test light will not give you a voltage reading but it will give you a go no go indication Testing a relay is a good example Our pump and master relays are four post relays The large posts are the contacts and the small posts are for the coil Do you have power to the relay Do you have power through the contacts of the relay Do you have a ground for the coil Do you have power to the other side of the coil These are questions that can be answered accurately with a test light And in many cases because of the location of the equipment it is easier to access the relays with a test light instead of trying to find a way to read the meter while holding the leads in place It may be necessary to use a meter in cases when a voltage problem is suspected but most of the equipment we use will operate at a low enough voltage that a test light normally will give you the information you need to make a repair A relay will turn on with 8 0 volts If y
73. e yourself when possible plenty of bare wire to work with so you can tightly twist the splice wires together Do not try to solder corroded wires or terminals 2 Remember to put the shrink tube onto one of the wires BEFORE you solder the splice Don t let the shrink tube get too close to the splice while soldering You don t want to shrink the tube before it is in place 3 Don t get the wires too hot This can damage the wire insulation and cause shrink tube to shrink before it should 4 Don t try to coat the splice with solder Heat the wire so the solder can wick into the wire strands Apply the heat to the bottom of the splice if possible A small drop of solder on the soldering tip can help transfer the heat to the wire when the tip is applied to the wire 5 Don t use too much solder Excess solder could cause a problem for the shrink tube Excess solder can wick up into the wires damaging insulation This will also cause the wire to be stiff away from the splice When all the visible wire strands are coated that is enough solder 6 Allow the splice to cool slightly before trying to move the shrink tube into place Too soon may cause the shrink tube to stick before it is in the proper position This is the end of this school at this time There may be future additions to this such as a schematic or diagram reading section Check the school outline from time to time We will mark future additions as New
74. ed 4 Insert the contact into the crimping tool 5 The end of the contact should be flush with the crimping tool cover If adjustment is needed loosen the lock nut for the contact depth adjustment screw and turn the screw until the contact is at the proper depth Tighten the lock nut 6 Insert the wire into the contact and pull the crimping tool handles together until they release 7 Remove the wire and contact from the tool Make sure all wire strands are in the contact and gently try to pull the wire from the contact to check the crimp ADJUSTING SCREW LOCK NUT ADJUSTING SCREW WIRE SIZE SELECTOR WIRE SIZE SELECTOR Fig 43 Contact and connector assembly for Deutsch connectors is fairly simple The wire and contact assembly just pushes into the connector through the wire seal Be careful to not damage the wire seal while inserting the wires into the connector Refer to drawings to make sure the wires are in the correct position in the connector To install cavity seals or key pins simply push the cavity seal or key pin through the wire seal in the correct position When all contacts cavity seals and key pins are installed push the wedge in place Make sure all seals are in place and gently pull on the wires to make sure they are locked in place by the wedge 2 14 1 2 Packard Weather Pack Connectors We simply refer to these connectors as Packard connectors Packard connectors are water resistant and are available with di
75. ed valve and is activated by switching voltage This is a high flow valve and is used on tag axle air manifolds This valve is not interchangeable with other hi flow valves Be careful not to confuse this valve with the AP1940 valve There is no visible difference between the two valves This is a normally closed valve and is activated by switching voltage This is a high flow valve and is used on active air system manifolds This valve should not be interchanged with other hi flow valves This valve will flow air through the top port when not activated When activated the top port is closed and the manifold port is open This valve is activated by switching voltage This valve is used on tag axle air manifolds for the tag lift and also is used on the air seal manifolds This is a normally closed valve and is activated by switching voltage This is the basic valve and is used in several different valve arrangements This valve is not mounted on a manifold It is us d on older air leveling systems on some air compressors and is used as a suspension air dump valve for hydraulic leveling systems AP5868 AIR VALVE IN OUT This is a normally open valve and is activated by switching voltage This is the basic valve and is used in several different valve arrangements This valve is used on air compressors Fig 24 26 This is a normally closed valve and is activated by switching vol
76. embly just pushes into the housing The wire cover protector must be open to install the wires Hold the wire directly behind the wire seal and push the wire contact assembly into the housing You will feel a light snap as the locking lances catch on the housing Push the cover protector closed until the cover snaps over the locking tabs Give the wire a light tug to assure the wire assembly is securely in place Check that the wires are in the correct slots before reconnecting the plugs 2 14 1 3 UML Universal Mate N Lock connectors These connectors are not weather tight and should not be used where water or moisture is a concern We use only one style of UML with several different wire number capacities ranging from 2 pins to 15 pins The mating halves have an arrangement of D shaped towers and receivers This assures the plugs will be connected correctly The mating halves also have a latch mechanism to make sure the connectors will not come apart inadvertently The contacts have locking lances to keep the contacts from coming out of the connectors It is important to note the UML contacts and the Packard contacts are very similar in appearance The UML contacts are slightly smaller These contacts are not interchangeable They use different crimping and removal tools The pin contact is usually used with the receiver half of the connector and the socket is used with the tower half We do not use key pins but sometimes when necessary we reverse the pla
77. es are no longer used The poly fuses are only used on pc boards in control boxes or panels Glass buss and blade fuses have a conductor that burns and creates a break in the circuit when the current rating of the fuse is exceeded Circuit breakers have contacts that will open when the current rating of the breaker is exceeded 6 Circuit breakers can be reset automatically or manually The use of automatic circuit breakers is not recommended Poly fuses are unique in the fact they don t have to be replaced or reset after tripping As the current rating of the poly fuse is exceeded the heat will cause the material of the poly fuse to totally resist the flow of current The poly fuse will remain open until current is removed from the supply side of the fuse or the overload or short is removed from the load side of the fuse Fuse size is very important Something that is quite often overlooked is the traces on pc boards Fuses are also sized to protect these traces Correct fuse size must always be maintained When too large a fuse is used the wiring or traces are put in jeopardy Traces can easily be burnt when fuses are oversized and this usually is an expensive repair Wiring can overheat which can cause a fire This is an even more expensive repair Too small of a fuse will not usually cause damage but will certainly affect the performance of the system by causing a break in the circuit even though the circuit is operating well within its
78. es may have a single pin Packard connector with the other wire having a ring terminal that is attached to the manifold The system pressure switch will complete a ground circuit when the vehicle system air pressure drops to the rating of the switch There are several different rated switches used There is an 85 psi switch and a 100 psi switch The system pressure switch is only used as a warning switch When system pressure drops to the switch rating the contacts of the switch close This completes a ground circuit to the control system The control system will then turn the warning indicators on Unlike the air bag pressure switches there is no delay between the switch contacts closing and the warning indicators coming on In wiring diagrams in owners and repair manuals pressure switches are simply drawn as they physically look When drawn in schematics we use the following symbols The pressure rating is listed next to the switch HYDRAULIC OR AIR SCHEMATICS ELECTRICAL SCHEMATICS NORMALLY 3000 PSI NORMALLY OPEN VV SWITCH OPEN 3000 LB PRESSURE SWITCH NORMALLY 3000 PSI NORMALLY CLOSED VV SWITCH CLOSED 50 LB PRESSURE SWITCH Fig 22 2 9 8 Pressure switch diagnostics Pressure switch diagnostics is much like diagnosing a warning switch all the pressure switch does is open or close a circuit Most of the diagnostics can be done with a test light continuity tester or some jumper wires In some cases it may be necessary t
79. esistor on the warning switch wire and a 100 ohm resistor on the pressure switch wire These two resistors end up in a parallel circuit when both the warning switch and the pressure switch are on The total resistance in this circuit is approximately 81 ohms If only the warning switch is on the circuit resistance is 480 ohms The following diagrams show the 3 wire switch circuit in three steps both switches off with only the warning switch on and with both the warning and pressure switches on 16 The diagrams show what the resistance values will be when measuring at different points on the switch Actual measured values should be within between 5 and 10 percent The switch circuit is the same for the kick down or straight acting style warning switch with either a single pin or 2 pin Packard connector WARNING SWITCH Le HARNESS IGNAL WIRE ss 1 CONNECTION open l ROUND WIRE 100 ono OU Ly JACK PRESSURE SWITCH WARNING SWITCH Ne HARNESS IGNAL WIRE pe a gt CONNECTION ZW 430 ERN 2 100 GROUND WIRE ey et JACK PRESSURE SWITCH WARNING SWITCH 100 0 52 1 o HARNESS IGNAL WIRE CONNECTION 5 81 _
80. fferent number of wire capacities and in different colors We use single pin 2 pin 3 pin and 4 pin connectors The 4 pin connectors are available in a flat or square pin arrangement The 2 3 and 4 pin connectors are labeled with letters for wire placement A B C or D Most of the connectors we use have been black but several years ago we started using gray colored Packard connectors for jack down warning switches We also use a 3 pin red connector on Hall Effect switches The different colored connectors are keyed so they cannot be plugged into each other We do not use key pins with the Packard connectors so it is important to mark connection and refer to diagrams when disconnecting and reassembling components with the same colored connectors Packard connectors have a latching mechanism to hold the mating halves together You just lift the latch over the locking clip and pull the connectors apart The contacts have locking lances to keep the contacts in the housing 2 PINPACKARD 2 PINPACKARD TOWER SHROUD ay w gt SOCKET PIN SLEEVE LOCKING CLIP Fig 44 42 Wire and contact removal for Packard connectors is accomplished with a special tool Connectors with similar contacts use a like tool but the diameter of the contacts is slightly different Using the wrong tool may not work and could cause damage to a contact or housing When the tube of the tool is slid over the
81. g light circuit for that particular jack As the jack swings to the vertical position the ball in the switch rolls into the two contacts of the switch completing the circuit This supplies a ground for the jack warning light and the processor if applicable These switches can be adjusted to come on sooner or not come on as soon by bending the switch up light doesn t come on as soon or down light will come on sooner Older kick down switches contain a mercury switch and should be disposed of properly when replaced The older switches function the same way the new switches 11 9000 Jack 9000 Jack Vertical Position Horizontal Position Zi WARNING SWITCH SO Two Wire 4 Kick Down 3 Warning Switch WARNING 5 SWITCH GROUND ii ENHANCEMENT BA WIRE Ny 3 SIGNAL 5 yy WIRE Fig 14 The connection for the warning switch to the warning switch harness is presently a two pin Packard connector The harness has two wires for the switch One is the ground supply from the control box or panel the other is the signal wire for the warning light circuit at the control box or panel Where the wires are inserted into the connectors for the harness and the switch the connectors are labeled A and B The ground wire is inserted in the
82. hen they are supposed to There is no continuity between the proper terminals of the switch Do the contacts close when they are supposed to There is continuity between the proper terminals of the switch Or simply is there power through the switch when there is suppose to be power and is there no power through the switch when there is not suppose to be power 2 2 ELECTRIC COILS are not an individual component in our systems but coils are used in relays and solenoid valves and it is important to understand how coils function A coil is nothing more than a long wire wrapped around a spool like a spool of thread When power and ground are applied to the opposite ends of the wire it creates a magnetic field that makes the core move This opens or closes the electrical contacts of a relay or opens or closes the seat of a valve All coils have a resistance value which can be checked but there is an easier way to check components that have a coil Components with coils are rated for a particular voltage 12 or 24 in our case These components also have a minimum voltage at which they will operate or pull in and when they will drop out An example of this is our solenoid valves The valve must pull in at no more than 8 5 volts and stay energized not drop out until the voltage drops to 2 volts or less If you check components with a coil in this manner the resistance value of the coil is not needed If a solenoid valve will not pull in until 9 volts the
83. ight come on When you ground the pin for the left side level light does that light and only that light come on When you ground the pin for the right side level light does that light and only that light come on If the answer to all five questions is yes the problem is the sensing unit If the answer to any of the five questions is no there is a problem with the control box or panel When making these tests after checking the ground supply pin use that pin to test the other four pins 36 When testing electronic sensing units of either style there are six questions to answer Five of the questions are the same as with the mercury sensing unit Is there a ground on the ground supply pin Is there voltage on the voltage supply pin When you ground the pin for the front level light does that light and only that light come on When you ground the pin for the rear level light does that light and only that light come on When you ground the pin for the left side level light does that light and only that light come on When you ground the pin for the right side level light does that light and only that light come on OY ae a If the answer to all six questions is yes the problem is the sensing unit If the answer to any of the six questions is no the problem is the control box or panel Check the ground pin against the voltage pin when making the tests If your light does not come on you k
84. ing the proper tools and techniques used to accomplish this The type of connector or terminal used is normally determined by the application Maybe moisture or some other type of contamination is an issue The number of wires that need to be in one connector may limit the type of connector available We use single wire connectors and multiple wire connectors including a round Deutsch connector capable of joining up to 31 wires Current carrying capabilities may be the determining factor Some connectors are limited to a maximum wire size which limits the current capability of that connector It is important when making repairs that correct connector pin and wire size are maintained It is also important to use the proper equipment and assembly procedures when repairing or working with connectors There are some important things to understand that are common to most connectors 1 Connectors have mating halves usually a male and female connector half Each of these halves house a contact These contacts are referred to as the male pin or the female socket also referred to as a sleeve For the remainder of this section we will refer to these as the pin or socket Normally the pin will be housed in the female half of the connector The socket will be housed in the male half of the connector Be careful this is not a 100 rule ROUND DEUTSCH CONNECTOR PIN CONTACTS SOCKET CONTACTS FEMALE MALE MATING MATING HALF HALF
85. ircuit A wire may not be properly crimped into the pin again causing a loose connection A pin may not be properly inserted into the connector When the mating connectors are pushed together the improperly inserted pin may push back causing a weak or loose connection Often when a connector or connection is not considered when diagnosing issues a complete harness or component is replaced Although the problem is fixed the actual problem was not addressed It is even possible the problem may return if the connector that was the issue is not the one that is replaced The reason the problem is or seems to be fixed is that when the new connector is assembled to the existing connector good enough contact is made so the problem seems to be gone for the time being Or if the problem was with the connector that is replaced the repair ends up being more expensive than it should be That is a disservice to the customer or the company that may be paying warranty Connector issues can usually be fixed by taking care of one wire or pin connection if the connector housing is not damaged It also may kick a warranty claim back if the part tests good when returned under warranty 2 14 1 Common types of connectors and terminals used by HWH In this section we will discuss the different connectors and terminals we use along with the insertion and removal of connector pins and the assembly of the wire to a connector pin or terminal This will include discuss
86. itch they must also see the 3000 psi system pressure switch before going to the next sequence room extend or room retract The same is true with the room in out limit switches When the controls see a room in switch they must also see the 3000 psi system pressure switch before engaging a room lock or shutting the pump off 2 9 3 50 psi hydraulic manifold pressure switch The 50 psi manifold pressure switch is a single wire information switch produced by HWH This switch is only used on 310 series 305 325 series 625 series and 2000 series leveling systems This switch is a normally open switch and completes a ground circuit when the contacts of the switch close as the system pressure reaches 50 psi This switch must be installed on the manifold so it comes after the shuttle valve in the hydraulic circuit The 50 psi manifold switch is used to let the controls know the shuttle valve has shifted and jack solenoid valves can be opened With manual leveling systems jack solenoid valves cannot be opened electrically until the controls see the 50 psi manifold pressure switch 2 9 4 5000 psi hydraulic synchronizing cylinder pressure switch The 5000 psi sync cylinder pressure switch is a safety switch that is only used on four cylinder room extension systems The 5000 psi switch is a normally open single wire switch produced by HWH Some four cylinder sync cylinders used a two wire 4000 psi pressure switch There is one pressure switch on each chamber of the s
87. itch is removed with the jack retracted The new switch cannot be inserted into the cylinder unless the cylinder is extended several inches To replace a side port switch extend the jack several inches Remove the foot of the jack or place blocks between the foot and the barrel of the jack to prevent the rod from retracting When the switch is removed the oil will be released from the jack and the rod will retract if not restrained Unplug and remove the switch from the jack and install the new switch The switch needs to be tight but an o ring seals the switch so be careful to not over tighten the switch Do not use a thread sealant on the threads of the switch Replace the foot and springs or extend the jack slightly so the blocks can be removed If the switch is removed with the jack retracted remove the spring from the end of the switch and use the old switch as a plug so the jack can be extended The drawings in Fig 15 show the side port switch and also the 2 inch plunger warning switch The plunger switch will be discussed next Although neither of these switches is used in production at this time replacement switches are still available Side Port Switch 2 Inch Plunger Switch th 2221 22 Fig 15 2 8 2 2
88. ith this type of system The diagnostics remain the same as above Simply unplug switches or ground wires to test the warning light circuit Adaptor with Resistors PRESSURE SWITCH PLUG F c 5 m HARNESS PLUG te WARNING lt SWITCH PLUG The systems with three wire warning switches can experience severe grounding issues that can make the system operate very erratically during the automatic leveling procedures especially during the stabilizing mode For complete diagnostics of the 3 wire warning switch and pressure switch circuit along with detailed instructions for grounding this system refer to ML9138 in the service manual section of the HWH web site 2 9 PRESSURE SWITCHES HWH uses pressure switches for many different reasons Pressure switches are used with hydraulic leveling systems room extension systems and air leveling systems At this time all pressure switches are used to complete a ground circuit except the pressure switches used on our air compressor assemblies used in air leveling systems Pressure switches can be a one wire or two wire switch The one wire switch is an internally grounded switch These switches rely on a good ground through the piece of equipment they are attached to Two wire switches rely on a ground supply wire in the harness Some of the switches we use are produced by HWH but not
89. les just enough to hold the contact in place Make sure the crimp wings are centered 4 Insert the bare wire into the wire crimp barrel of the contact and squeeze the handles together Remove the contact from the crimp tool and gently try to pull the wire from the contact to check the crimp 5 Reposition the contact in the crimp tool with the insulation crimp wings centered in the crimp marked INS Pull the handles of the tool together 6 Remove the wire and contact assembly from the tool and visually inspect both crimps AMP UML CRIMPTOOL Sor p prn CHAMP FT 3 i ie see to 3 ri 8 LH E e INSULATION CRIMP BARE WIRE BARE WIRE CRIMP AND CRIMP DONE INSULATION CRIMP DONE BEFORE CRIMPING Fig 50 Contact and connector assembly for UML connectors The wire and contact assembly just pushes into the housing Hold the wire directly behind the wire insulation crimp and push the wire contact assembly into the housing You will feel a light snap as the locking lances catch on the housing Give the wire a light tug to assure the wire assembly is securely in place Check that the wires are in the correct slots before reconnecting the plugs 45 2 14 1 4 MTA Mass Termination Assembly connectors We use two types of MTA connectors a self stripping connector and a crimp style connector These are not weather tight connectors and should only
90. llows the operation of the system Anytime a problem is encountered while using the manual the manual will explain what to check where to check and what to check for The main thing to remember is the control boxes and panels function on the power in and power out theory Making sure that the voltage and ground for the control panel or control box is within operating specs is usually the first thing you will want to do Once you establish you have good voltage and ground for the panel or box you can diagnose the problem The following are a couple of examples A solenoid valve will not open Do you have power to the box No power If there is no power to the box the box cannot work If there is power then do you have power on the correct output pin for that valve If there is power on the output pin for the valve the problem is not the box If there is no power on the output pin check the appropriate fuse If the fuse is blown the problem is most likely not the box If the fuse is good the problem is most likely the box iad SS POWER IN OUTPUT PIN FUSE 7 SOLENOID VALVE CONTROL BOX Fig 12 10 One warning light will not come on If other warning lights are working voltage and ground is probably not the issue Still a good idea to check it Do you have a ground on the appropriate pin for that warning switch No The problem is not the box or panel Yes The control box or panel
91. lot of a two wire harness If the warning indicators come on the problem is at the switch If the indicators don t come on the problem is the harness or the light plate control panel or control box For two wire switches you should be able to short the two pins in the harness plug together and turn the warning indicators on If the indicators come on the problem is the switch If the indicators don t come on the problem is the ground in the harness the signal wire in the harness or the light plate control box or control panel Using a meter to check for continuity through the switch to ground is not usually necessary Grounding the signal wire B wire in the harness will give you the information you need 2 8 4 3 wire warning switches The 3 wire switches are only used on jacks for the early 610 series leveling systems that ARE NOT centrally grounded There are two basic types of 3 wire switches There is a switch for the kick down jacks and one for straight acting or fixed jacks The early version of these switches had two single pin Packard connectors and a long ground wire with a ring terminal The single pin shroud connector was for the jack pressure switch The single pin tower connector was for the harness connection On present switches the ground wire is in a two pin tower connector with the signal wire for the switch The jack pressure switch connector is still a single pin shroud connector Early systems will have only one wire the sig
92. m the connector The removal tool for the UML contacts is a plunger style tool Slide the tube of the removal tool over the contact until the tube bottoms out on the connector Push on the tool This will pop the wire out of the connector If the wire does not pop out try pushing the wire farther into the connector while sliding the removal tool onto the contact Then push on the tool The wire and contact should push out of the connector UML REMOVAL TOOL LOCKING LANCE 458994 1 Fig 49 Wire and contact assembly for UML connectors A standard style crimping tool is available from HWH to make the UML wire and insulation crimps This is a reasonably priced tool Terminal applicators from other sources to do the UML crimps are available also HWH can supply the special crimp tool that performs both crimps at once but this is a very expensive tool and is not really necessary to have The crimp tool from HWH for the UML connectors is adequate and will be the only crimp tool discussed in this section HWH uses contacts that will accommodate 12 14 16 or 18 gauge wire Contacts for smaller gauge wires are available The following steps are for making the two crimps to apply the wire to the UML contacts 1 Strip 1 4 inch of insulation from the wire 2 Choose the appropriate wire crimp position on the tool 3 Position the wire crimp barrel in the crimping tool and close the hand
93. n compared to checking voltage The main thing to remember when checking resistance is that the circuit must be off It is also best that the circuit or component is isolated The main problem with checking circuit or component resistance is obtaining a resistance value The other issue is the capability of the meter that is available For example our large solenoid valve coils only have approximately 1 2 ohms of resistance Without a meter with a relative function you cannot get an accurate measurement Here are some resistance values for several gauges of stranded wire These values are per 50 foot of wire at 68 degrees Fahrenheit 10 gauge 054 ohms 12 gauge 0855 ohms As you can see you need the size and length of wire to determine resistance 14 gauge 1365 ohms of the wire in the circuit Even small gauge wires have a very low resistance 16 gauge 2175 ohms factor Voltage drop for individual components is the best way to diagnose 18 gauge 346 ohms component issues 55 Using a meter to check voltage is the most reliable and accurate way to check voltage and corrosion or connection issues I still like a test light for initial quick tests especially when a component will not function at all Checking voltage drop is the best way to diagnose a circuit There are three main things to do when checking voltage drop with a meter 1 You want to check as close to the component with the component plugged in as possible This should be
94. n try to count the components on one of the more complicated pc boards Let me know if you want to I will send you a schematic It may seem like I am trying to overwhelm you with how complicated systems are but that is not my intention I just want you to know the range of what we deal with here at HWH The important thing to realize is that no matter how simple or complicated the control box or panel is the diagnostics for each one is fairly simple if you understand how the system operates and how the components function Many of the system components that the control boxes or panels work with are the same no mater what system you are working on A solenoid valve is a solenoid valve a warning switch is a warning switch a relay is a relay and etc All any box or panel does is receive information and send out control signals REMEMBER POWER IN POWER OUT All boxes and panels have connectors to link them to the system components such as the valves relays warning switches or pressure switches to name a few Although some are more readily available than others there are diagrams available for all boxes and panels that will label the inputs and outputs This will tell you which connectors and which pins are connected to which system components And once you understand how the different components function you are almost home This section of the school 2 ELECTRICAL COMPONENTS is probably the most important section of the Electrical School Maybe the
95. nal wire to each jack in the harness The later systems have two wires in the harness a ground wire for the warning switch and the signal wire Replacement 3 wire warning switches come with an adaptor that will connect a warning switch with a 2 pin Packard connector to a 1 wire harness with a single pin Packard connector or no connector Three Wire Kick Down Jack Three Wire Straigh Acting or Fixed Jack Warning Switches Warning Switches HARNESS m GROUND hH HARNESS leal HARNESS CLH eee oe eps PRESSURE 4 PRESSURE PRESSURE SWITCH SWITCH SWITCH Fig 18 The 3 wire warning switch was developed to allow the use of one signal wire in the harness to each jack even though each jack has two information switches Each jack has a warning switch and a pressure switch The warning switch is for the jack down warning lights and the pressure switch is used during the stabilizing mode of automatic leveling to let the computer know the jack is on the ground The 610 non central grounded leveling system will be discussed in greater detail in Lesson 13 of the HWH ONLINE SCHOOL The 3 wire warning switch has two resistors incorporated into the assembly There is a 430 ohm r
96. ndicator lights to show incoming signals Do not check the signal wire of a Hall Effect switch with a test light Damage to the switch may occur 24 When a magnet is close to the switch the switch is activated This puts a ground on the signal wire Make sure the room is in the proper position fully extended or retracted Most if not all controls will have indicator lights to show incoming signals Check the appropriate indicator light If the light is on the switch is not the problem If the light is not on the proper way to check the switch is to first check for ground and positive voltage on pins A and B Unplug the switch while testing If either is missing that must be addressed first The switch cannot function without power and ground If both are present ground the signal wire pin C in the harness Check the control box to see if the controls recognize the ground signal If the controls are seeing the ground signal plug the switch back in and use an external magnet to activate the switch Again check the indicator light If the indicator light is on the switch is working The problem is most likely the position of the switch or magnet Adjust as necessary If the indicator light does not come on the switch is faulty Vacuum switch for air seal manifolds This is a normally open switch that will complete a ground circuit when the contacts close With no air exhausting from the manifold the contacts of the switch should be open no con
97. new switch and be careful to not over tighten the switch The switch uses an o ring seal Plug the switch in and test the system Two Wire Magnetic Warning Switch 2 PIN PACKARD GRAY WARNING tL SWITCH gt SIGNAL GROUND WIRE gt WIRE 2 1 ROD GROUND PORA ENHANCEMENT ud WIRE MAGNET 2 8 3 One and two wire warning switch diagnostics Warning switch diagnostics is usually a simple process of elimination Start by isolating the circuit or circle The main components of the circuit are the warning switch the harness and the control box light plate or control panel The following diagrams show three circuits a central grounded two wire warning switch this would be what is presently being used a non central grounded two wire warning switch and a non central grounded one wire warning switch They are drawn with the switch open as if the jack would be retracted The warning light would be off Two Wire Switch Central Grounded System LIGHT PLATE WARNING LIGHT HARNESS SWITCH ts SIGNAL WIRE P ne GROUND WIRE 1 1 11 a ae gt gt
98. ng valves This allows the tests to be done with the pump motor under a full load Voltage test This test must be done while trying to run the motor Check the voltage by putting the meter lead on the motor voltage stud Use the pump housing for the ground lead If you have a 8 0 volts or more the pump motor should be running 8 volts is not very good voltage and it should be determined why the voltage is that low but the pump motor should still run It you have less than 8 0 volts locate a good ground that is adequate for the motor and recheck Resistance in the pump mounting could be the issue Also check the voltage at the pump relay Make sure the problem of low voltage is not a connection at the motor 625 SERIES PUMP MANIFOLD CONTROL BOX ASSEMBLY N o PUMP HOUSING MOTOR off HWH GROUND STUD MOTOR STUD Another problem that may occur is a noisy motor If the bushings of the motor become corroded this can cause a grinding noise in the motor The motor should be replaced This can be more common with systems that are not used regularly None of the motors are sealed and water resistant Moisture can build up in the motor causing oxidation between the shaft and bushing If the motor is not run occasionally this can turn into corrosion Causing a noisy motor
99. nnector at a 90 degree angle and is held in place with a retaining latch When the wire is pushed in a slot in the contact cuts through the wire insulation to connect with the wire strands The end of the wire should be cut as straight as possible The insulation should not be stripped from the wire 47 There are several hand tools available to perform this job The MTA wire insertion T handle is an inexpensive tool that is used to insert the wires The end of the tool has teeth that fit into the connector and connector contacts This tool will only insert one wire at a time It is best to have a solid surface to rest the connector against while pushing the wire into the connector Lay a wire in the appropriate slot of the connector and use the T handle to push the wire into the connector Push the T handle as far as it will go The other tool available is fairly expensive but is a good tool to have if it is necessary to insert a number of wires into MTA connectors This is a pistol grip tool that will advance the connector to the next slot each time the trigger is pulled After the connector is inserted into the tool the wire is inserted into a slot in the tool until the wire bottoms out Pulling the trigger will push the wire into the connector to the proper depth and advance the connector to the next slot If a wire is not needed in the next slot simply pull the trigger to advance the connector Check wiring diagrams to make sure the wires are in the
100. not protect the connection 50 Crimping solderless terminals To start always use a good quality crimping tool The heavier the crimping tool is the easier it is to obtain a good solid crimp If using a special terminal check if the manufacturer requires a special crimping tool For stripping insulation from the wire use a wire stripper that is designed to be able to strip specific wire gauges Do not strip more insulation from the wire than is needed Normally about inch is adequate Do not use side cutters or a knife to strip wire This could nick some of the wire strands causing them to eventually break This will decrease the current carrying capability of the wire Many crimping tools have a hump on one half of the crimp and a half circle on the other half of the crimp Most solderless terminals have a closed barrel for the wire crimp This barrel usually has a seam When crimping the terminal make sure the hump of the crimp tool is placed opposite the barrel seam This will keep the seam from spreading when the crimp is made HEAVY DUTY CRIMP TOOL BUTT CONNECTOR TERMINAL INSULATION CRIMP Pt INSULATION Fig 61 RING TERMINAL 3 ELECTRICAL TEST AND REPAIR EQUIPMENT The first section explained how different electrical components function along with basic diagnostics for those components This section will deal with the test and repair equipment needed to put the first section to work The two main pieces of test equipment w
101. now there is a problem with the control box or panel If those two pins are ok use the ground pin to test the other four pins for the level sensing lights Hint If testing an electronic sensing unit that is mounted in a control box and you have no diagrams handy the sensing unit board is labeled with the wire function where the wire attaches to the board LS is the yellow wire left side F is the black wire front RS is the green wire right side R is one of the red wires rear GND is the white wire ground and 12V is the last red wire voltage You can follow the wires to the connector to determine which pin is which There are several other issues that may arise with sensing units that there is really no test for In most of these cases you have to make a judgment call If a sensing unit does not want to adjust it seems like the sensing unit is too sensitive you may have to replace the sensing unit If the complaint is the sensing unit will not stay in adjustment the problem is more than likely the mounting of the sensing unit or power unit The sensing unit must be mounted to a solid surface that will not flex or move Sometimes a power unit may need a brace to limit movement and vibration Think about where the sensing unit is mounted Is it in a compartment Maybe the sensing unit is bumped when the compartment is loaded or unloaded Just make sure the sensing unit is mounted solidly and protected from being bumped 2 14 EL
102. o have a pressure gauge available When testing hydraulic pressure switches the gauge needs to be capable of at least 5 000 psi Most air systems we deal with would not exceed 150 to 200 psi It is important to know if the switch is switching a ground or a voltage This information can be found in repair manuals or in wiring diagrams Normally open pressure switches A normally open pressure switch should be totally open with 0 pressure in the system If the switch is a two wire switch the circuit should be open between the two wires of the switch If the switch is a one wire switch the circuit should be open between the switch wire and the body of the switch When testing the continuity of the switch it is best that the switch is unplugged When the pressure in a hydraulic or air circuit reaches the rated pressure of the switch the switch contacts should close There should now be continuity through the contacts of the switch 21 Normally closed pressure switches A normally closed pressure switch should have very low resistance between the switch contacts with 0 pressure in the system A two wire switch will show a closed circuit with little resistance between the two wires A one wire switch will show a closed circuit with little resistance between the wire and the body of the switch When testing the continuity of the switch it is best that the switch is unplugged When the pressure in a hydraulic or air circuit drops to the rated pressu
103. ors that allow the light to be easily connected to different plugs It is a good idea to purchase a test light that has an easily replaceable bulb Purchase a test light that you are comfortable with using and understanding 3 2 DIGITAL MULTIMETERS VOLTMETERS ETC Although in the Test Light section we discuss the usefulness of the test light you can only get an accurate measurement of voltage or resistance with a meter That is why it is important to know how to use YOUR meter This section is not going to explain how to use a particular meter There are many different styles brands and price ranges when considering meters This section will discuss general information to aid in the use and selection of Multimeters 3 2 1 Selection of a meter Up to a point how much you spend on a meter should not be a consideration There are very inexpensive meters available but again you get what you pay for 30 won t buy you much of a meter That doesn t mean you should run out and spend 500 or 600 either The two main considerations when purchasing a meter are quality and features For quality do some shopping Talk to several experienced techs and get some opinions Whether it s from an on site tool truck or a supply catalog make sure warranty and service is readily available for the meter For features you need to understand what you are going to work on If your work is limited to HWH type equipment you won t need the same features in a meter th
104. ou have less than 8 0 volts your test light will be dim Like all tools you need to know your test light Also you get what you pay for Buy a good test light and know its capabilities IF YOU ARE NOT SURE OF YOUR TEST LIGHT OR THERE IS ANY SUSPICION OF A VOLTAGE ISSUE CHECK THE VOLTAGE WITH A METER BEFORE CHANGING PARTS Remember the statements made in this school are based on experience with the equipment used by HWH and do not necessarily apply to everything that you will work on in the RV industry 51 Here are some rules for using the test light for diagnostics 1 Know your light Know the difference between bright and dim At what voltage do you start to notice a difference 2 Know the equipment you are testing At what voltage will the equipment function Should you use a test light on certain pieces of equipment Although most of the HWH equipment is designed so a test light can be used some equipment can be harmed by using a test light The Hall Effect switches and pressure transducers not pressure switches we use should not be tested with a test light There are other pieces of equipment this is true of Do not use a test light on printed circuit boards unless a service manual or service representative directs you to do so If in doubt ask 3 Know the voltage you are dealing with A 12 volt test light will burn out quickly on a 24 volt system 4 Be careful with the test light probe Because of the length of the pro
105. ou switching voltage or ground Is the relay a normally open or normally closed relay Is the relay coil controlled with a switched voltage or a ground Most of the relays we use draw less than 1 or 2 amps so operating a relay does not create much of a load a test light will usually do most of the diagnostics needed or at least give you the basic answers to the tests for relay diagnostics When helping someone diagnose a relay problem one statement I frequently get is my test light will come on when I touch either of the coil terminals You need to remember that a coil is just one long wire wrapped around a metal rod If there is voltage on both relay coil terminals there is no ground for the coil If there is a ground on both relay coil terminals there is no voltage to the coil of the relay GND 12 VOLTS gcor COIL H ND 412 G 49 12 VOLTS VOLTS VOLTS Fig 4 Most of our relays should pull in at a minimum of seven to eight volts and stay on with less voltage If a relay is the relay contacts to stick or burn out Remember the ground for the relay could be the problem as easily as the voltage could be the problem Whether it is a voltage problem or a grounding problem low voltage will ruin a relay quicker than most other issues Also a very common problem with the relays on the pump is loose connections or corrosion An easy way
106. p style MTA connector The MTA contact has two crimps one for the bare wire and an insulation crimp The same crimp tool that HWH supplies for UML connectors is used to crimp the wire to the MTA contact The wire range for these contacts is 18 to 24 gauge The following steps are for making the two crimps to apply the wire to the MTA contacts 1 Strip 1 8 inch of insulation from the wire 2 Choose the appropriate wire crimp position on the tool The crimp with the orange dot will do 12 and 14 gauge wire 3 Position the wire crimp barrel in the crimping tool and close the handles just enough to hold the contact in place Make sure the crimp wings are centered 4 Insert the bare wire into the wire crimp barrel of the contact and squeeze the handles together Remove the contact from the crimp tool and gently try to pull the wire from the contact to check the crimp 5 Reposition the contact in the crimp tool with the insulation crimp wings centered in the crimp marked INS Pull the handles of the tool together 6 Remove the wire and contact assembly from the tool and visually inspect both crimps AMP UML CRIMPTOOL ie gt y E A Ja Meer Ta No gt INSULATION WIRE oe spate INSULATION UNCRIMPED SOCKET CRIMPED ASSEMBLY Fig 55 Wire contact and connector assembly for MTA connectors Self stripping style MTA connectors The wire pushes into the co
107. proper slots PISTOL GRIP T HANDLE WIRE INSERTION TOOL WIRE INSERTION TOOL 82 WIRE INSERTION SLOT WIRE INSERTION TEETH Fig 56 Crimp style MTA connectors The wire and contact assembly simply pushes into the housing It will only push in one way Push the assembly into the connector until you feel the locking lance click into place Gently pull on the wire assembly to make sure it is locked in place Check wiring diagrams to make sure the wires are in the proper slots 2 14 1 5 EJS connectors Econoseal J series by AMP This is a weather tight connector It has two mating halves the plug and the receptacle The plug has the pin contacts and the receptacle has the socket contacts We use a 6 pin and a 12 pin connector in this style This style connector is used on the main harness connection along with the level sensing unit connection to the 210 225 joystick valve It is also used to connect the potted electronic level sensing unit to a harness The mating halves are keyed and cannot be plugged in backwards The mating halves have a locking mechanism to keep the halves together The latch must be depressed to separate the mating halves The pin and socket contacts are held in the housings with a spring type latch and wedge The connectors are a two crimp connector One crimp for the bare wire the second crimp is for the wire seal It is important to note there are no marking
108. puterized bi axis leveling system with 14 control box AIR amp HYD 610 series touch panel controlled computerized bi axis leveling system HYD ONLY 610 series touch panel controlled central grounded computerized bi axis leveling system HYD ONLY 625 series touch panel controlled computerized bi axis leveling system HYD ONLY 625s series touch panel controlled single touch computerized bi axis leveling system HYD ONLY 680 series touch panel controlled computerized bi axis leveling system rooms with hydraulic locks AIR amp HYD 700 series touch panel controlled single touch computerized bi axis leveling system AIR ONLY 725 series touch panel controlled single touch computerized bi axis leveling system HYD ONLY 2000 series touch panel controlled CAN computerized bi axis leveling or room control systems AIR amp HYD Most of our leveling systems have a repair manual that is available on the HWH web site but you need to know which system you are working on to get the correct manual There are several different 610 325 and 625 repair manuals It is very important to get the correct manual On the HWH website under Customer Support amp Technical Service you will find Leveling System Identification This section will give you visual and written information to help identify which system you are working on Click on Leveling System Identification to link to this site You can also use the Parts Catalog on the web site under
109. r total system failure Although HWH has used different size diameter pump motors in the past present HWH pumps except Oildyne pumps are equipped with either a 3 7 motor or a 4 5 motor HWH recommends a 2 gauge cable for the 3 7 motors if the cable length is less than 35 feet Lengths over 35 feet may create an unacceptable voltage drop and need to be a larger gauge diameter HWH recommends a 1 O gauge wire for the 4 5 motors if the cable length is less than 35 feet Lengths over 35 feet may create an unacceptable voltage drop and need to be a larger gauge diameter The recommended fusing for the 3 7 motor is 150 amps The recommended fusing for 4 5 motor is 200 amps 4 Grounding of the pump motor is as important as the voltage supply cable Except for one Fenner Stone pump motor used in the early 1990s and the small Oildyne pumps all other pump motors used by HWH are internally grounded The motor relies on the mounting of the pump for a ground If the mounting surface for the pump will not supply an adequate ground a separate ground cable must be applied to the pump It is important to remember that the ground for the pump must be at least equal to the size of the cable that supplies voltage to the motor Oildyne pumps and other present day pumps are supplied with a ground stud for centrally grounding the system This stud can be used to attach a grounding cable to 5 The motor armature is like a coil As the amount of cu
110. rated capacities The main thing to remember about fuses when diagnosing fuse issues is only an overload or short on the load side of a fuse will cause a fuse to open or trip No issue on the voltage current supply side of the fuse can cause a fuse to open or trip FUSE PUMP PUMP 200 AMP RELAY MOTOR aa 6 12 VOLTS NOT PROTECTED PROTECTED Fig 8 2 5 DIODES are electronic devices used to control the direction current can flow A diode will only allow current to pass through in one direction The directions are referred to as forward and reverse bias A diode installed into a circuit with a forward bias will allow the current to flow through A diode installed with a reverse bias will block the flow of current There are different types of diodes including LEDs which are light emitting diodes We use many diodes and LEDs in our systems but most of them are mounted on pc boards or installed in a component such as the large solenoid valves and are not serviceable in the field It is not even important to be able to diagnose diode issues when they are part of component But sometimes when necessary a diode may be used in a harness When there is a diode in a harness the harness will have a DIODE label at the point where the diode is installed One way to check a diode with a meter is to set the meter to DIODE CHECK When checked in the forward bias the meter should read
111. re 2 9 2 3000 psi hydraulic manifold pressure switch The 3000 psi manifold pressure switch is a single wire switch produced by HWH This switch is an information switch Older systems may have a two wire switch that was not produced by HWH These switches can be replaced by the new 3000 psi switch A few very early computerized systems had a 2500 psi switch The 3000 psi switch is a normally open switch and completes a ground circuit when the contacts of the switch close as the system pressure reaches 3000 psi Although the switch is adjustable this should not be necessary The 3000 psi manifold switch is only used on computerized hydraulic leveling systems or on room extension systems which have hydraulic locks or room systems with room in out limit switches and air seals Normally the switch is on the leveling system manifold but may be on a room extension manifold if the vehicle does not have HWH hydraulic leveling The 3000 psi manifold switch monitors system pressure and is used to indicate an excess slope situation during automatic leveling 19 Example The two front jacks have extended as far as they can and the front yellow level light is still on When the system pressure reaches 3000 psi and the switch contacts close the controls stop the leveling procedure and turn on the EXCESS SLOPE light With room extension the controls must see the 3000 psi system switch when changing a sequence Example When the controls see an unlock sw
112. re adjustment Although the mercury sensing unit is no longer available it is possible that you may run into one that needs adjustment The most important thing to understand about sensing units is the accuracy tolerance of the sensing unit All HWH sensing units have an accuracy tolerance Due to the nature of leveling a vehicle a sensing unit with a tolerance of 0 degrees will not function properly Because of the movement of the vehicle the level indicator lights will bounce back and forth as the vehicle approaches a level position We have discovered over the years a tolerance of 2 to of a degree is the best tolerance to obtain a reasonable levelness of the vehicle On our adjustment sheets we change degrees to inches for our stated tolerance We use the example of a 36 foot vehicle When you do the math the tolerance figures out to be 5 4 inches front to rear and 1 inch side to side We use the same tolerance for the mercury and electronic sensing units This means if the vehicle is leveling within the tolerance of the sensing unit DO NOT adjust the sensing unit Make sure the owner of the vehicle understands the level sensor tolerance For a quick reference we tell people to use a round refrigerator bubble level If 1 2 the bubble is in the bulls eye the vehicle is level within the tolerance of the sensing unit Only the levelness of the vehicle can be adjusted The tolerance is set and cannot be adjusted Because a vehi
113. re of the switch the switch contacts should close There should be continuity between the contacts of the switch Knowing the function of the pressure switch will help determine if a pressure gauge is needed for the proper diagnostics of the switch Example 1 A jack pressure switch is not functioning correctly You do not need to take a pressure reading at the jack a jack pressure switch should close when the jack has lifted the vehicle approximately 1 inch The pressure at which this is achieved is not important only that the vehicle lifts about 1 inch Example 2 An automatic system will not show excess slope even though two jacks are fully extended and the vehicle is not level It will be necessary to determine that the system can develop more than 3100 psi The pressure switch will not close until the system reaches 3000 psi and the switch can be set at or 100 psi The problem may be the switch but could also be a shuttle valve or the pump itself Pressure switches may have some tolerance This would allow the switch to open or close at a slightly different pressure than the stated operating pressure of the switch A 20 psi air pressure switch may operate at 19 or 21 psi A 3000 psi hydraulic pressure switch may operate at 2900 or 3100 psi If the stated pressure and actual operating pressure of a switch seems too extreme contact HWH to obtain switch tolerance information 2 10 LIMIT SWITCHES Limit switches for HWH are only used with room
114. rk your way through the circuit the voltage should be the same If there is any voltage differences as you go there is some type of load on the circuit The open in the circuit is somewhere between the last good voltage reading you got and the first 0 00 reading you get FUSE SWITCH 12 7V ae Light On 12 7V ae Light as Light 85 Light On Off VOLTAGE SOURCE Solenoid Valve Light Off 0 00V Fig 62 Review the other sections of this school There are a lot of good examples of how to check circuits and system components Answers to the exercise in the Reading the digital multimeter section 1 0423 KQ 2 00173 KQ 3 236 V 4 639 700 Q 5 0361 mA 6 625 000 uA 7 8 360 mV 8 147 568 A 9 22 350 000 Q 10 00071 V 56 3 3 OTHER TEST AND REPAIR EQUIPMENT There is any number of pieces of equipment you could own but most of what you need has already been discussed in this school However there are some things that you will need or find useful when working on HWH equipment 3 3 1 Clamp on amp meter This meter is necessary to check the current draw of pump motors Most digital multimeters are only good for testing up to 10 amps This meter is available several different ways It can be purchased as a stand alone meter It can also be purchased in most cases as an accessory for your digital multimeter The accessory amp meter
115. rogramming direction JP3 and JP4 are used to program suspension type 35 The instruction brochure for programming of the electronic sensing unit is ML31215 The brochure is printed on one sheet front and back and contains information about jumper placement for sensing unit direction and for selection of suspension type Suspension selection is on the second page of the brochure The instruction sheet has four different views of the sensing unit in relationship with where the front of the vehicle is Pick the correct orientation of the sensing unit with the front of the vehicle Move the appropriate jumpers according to the sheet Make sure the jumpers that are needed are connecting the correct jumper pins If power to the control box is not off and the sensing unit remains plugged in while programming the sensing unit the new rogram will not override the existing program until power is removed from the control box The program chi has to reboot like a regular computer to accept the new program FRONT OF VEHICLE 1 2 D 6 Ut D af P X R JUMPERS PLEXIGLASS MOVE JP1 AND JP2 Fig 32 Hint To use the sheet properly lay the sheet on a flat surface and rotate the sheet to determine the orientation of the sensing unit to the front of the vehicle Another hint Program the sensing unit before in
116. rrent flowing through the armature increases and the length of time the current is flowing increases the temperature of the armature increases Except for the Oildyne pumps HWH pump motors have no thermal protection built in The rule of thumb is the pump motors should not run continuously under full load for more than three minutes without a cooling period Although pump motors can be replaced HWH does not have replacement motors for all different pump models Contact HWH for pump motor replacement information Some pumps have a coupler that joins the motor to the pump This coupler is not supplied with the new motor make sure to retain the existing coupler when removing the old motor Be careful to not let the armature come out of the new motor housing Reinstalling the armature can be difficult HWH uses a reversible pump manufactured by Oildyne This pump has three leads coming from the motor One lead is a ground The other two leads two leads determine the direction the motor spins Power on one lead will turn the motor clockwise Power on the other lead will turn the motor counter clockwise 31 2 12 1 Pump motor diagnostics Pump motor diagnostics consists of checking the voltage at the motor and sometimes checking the current draw of the motor with a clamp on meter Either test has to be done with the pump relay on trying to run the pump I like to use jumper wires to turn the necessary relays on That way the tests are done without openi
117. s or tabs to indicate correct wire positions on the EJS connectors You must use wiring diagrams and orientate the wires in the connectors as shown in diagrams EJS RECEPTACLE EJS PLUG il C WEDGE WEDGE Ul uUe at WIRE SOCKET PIN WIRE SEAL SEAL Fig 57 48 Wire and contact removal from EJS connectors The contact removal from the EJS connectors can be accomplished with an electronic screwdriver with a 050 blade First remove the wedge from the connector After the wedge is removed use the screwdriver to lift the spring latch while gently pulling the wire and contact assembly from the housing The latches are small and can be hard to see Do not force the assembly out This could ruin the assembly and the housing TOP AND SIDE VIEW OF WIRE AND PIN ASSEMBLY SPRING LATCH za LIFT LATCH 5 HERE LATCH CATCH Fig 58 Wire and contact assembly for EJS connectors A standard style crimping tool is available from HWH to make the EJS wire and wire seal crimps This is the same tool used for UML and MTA crimp style connectors The following steps are for making the two crimps to apply the wire to the EJS contacts 1 Slide the wire seal onto the un stripped wire with the small end of the seal towards the end of
118. s time that incorporate a level sensing unit have yellow level indicator lights on the control panel These lights are controlled by the level sensing unit Although the mercury style and the electronic sensing units are worlds apart in their design they both do the same thing the same way They control the yellow level indicator lights for all systems For computerized systems they give the processor the information needed to level the vehicle The way this is accomplished is by completing a ground circuit on the four level sensor pins Non bi axis systems have a level light for each corner of the vehicle left front right front right rear and left rear Bi axis systems have a level light for each end or side of the vehicle front rear left side or right side There is an electrical pin connection for each light When the vehicle is low on a side end or corner the sensing unit completes a ground circuit on the appropriate pin The only practical difference between the two types of sensing units is the electronic sensing unit is a six wire component and the mercury sensing unit is a four or five wire sensing unit The sixth wire for the electronic sensing unit is a voltage wire for the electronic equipment on the sensing unit 2 13 1 Level sensing unit adjustment All sensing units have to be adjusted after installation or if the sensing unit is removed and replaced Electronic sensing units installed in control boxes will have to be programmed befo
119. stalling the power unit or control box in the vehicle Depending on the mounting location of the control box the rubber gasket that attaches the clear plastic cover to the box can be difficult to install properly It is critical that the cover and gasket are installed properly to keep water out of the box 2 13 3 Sensing unit diagnostics This is the easiest part of our sensing unit discussion The only difference between diagnosing a mercury style and an electronic style sensing unit is the voltage supply wire for the electronic sensing units The potted electronic sensing unit may be a little more difficult to diagnose but only because of the connectors used We are developing a test plug for the potted sensing unit and it may even be available as you read this Testing for any style level sensing unit can be done with a test light In fact testing sensing unit problems is easier with a test light than a meter Present day systems will either have a five pin connector for mercury sensing units or a six pin connector for electronic sensing units I usually start my diagnostics at the control box or the control panel where ever the sensing unit attaches to For five pin mercury sensing units there are five questions Is there a ground on the ground supply pin When you ground the pin for the front level light does that light and only that light come on When you ground the pin for the rear level light does that light and only that l
120. t still would only have 10 32 ohms of resistance The damaged wire could cause a significant voltage drop causing a piece of equipment to fail even though the beep test indicated continuity Example 2 A circuit with a load that has a coil with approximately 1 ohm of resistance such as our hydraulic solenoid valves has a wire that was tested by someone poking a test light into the wire The wire now has a corrosion resistance of 1 5 ohms With a system voltage of 12 5 volts the voltage drop across the corrosion is 7 5 volts The solenoid valve will not work because of the wire but the beep test showed good continuity through the wire I am not saying to never use the beep test just don t rely on the beep test to be conclusive in connection and resistance issues 3 2 4 Using the multimeter The two main things you will use the multimeter for are checking voltage and resistance These two checks will take care of continuity tests Remember the beep test is very inconclusive The diode test is not a very common test either If a diode is causing an issue with a circuit board you don t have to diagnose the bad diode If a circuit board is failing we replace the board not internal components If the problem diode is in a harness power is getting through when it shouldn t or power isn t getting through when it should Either way a voltage test will show the problem Even checking resistance will not be very common whe
121. tage This valve is used on air compressors 2 11 2 Hydraulic solenoid valves Hydraulic solenoid valves direct the flow of fluid in our leveling systems room extension systems and other slide mechanisms There are presently two basic hydraulic solenoid valves They are simply referred to as the large and small valves The main difference between the two valves is the flow rate The large valve has a bigger seat orifice than the small valve Large and small valves should never be interchanged The flow of fluid would be changed which can affect the operation of the system Both the large and small valves are equipped with a 4 inch valve release nut for manually opening the valve in the case of an electrical failure When used with an auxiliary hand pump system the small valve is equipped with a valve release cam lever to manually open the valve Note As of April 2011 all small and large valves 12 and 24 volt for all leveling and room extension systems will be equipped with the valve release cam lever Both valves draw about the same amount of current the large valve using slightly more Also due to the design of the valves the large valve can remain on for a longer period of time without causing damage to the coil of the valve Both the large and small valves are available with either 12 volt or 24 volt coils Except for one valve the AP3572 all solenoid valves are operated by switching voltage This valve is only used with the
122. te the foot of the jack has extended slightly As with the kick down jacks the switch does not indicate the foot of the jack is on the ground The foot of the jack will extend between inch and 2 inches depending on the type of switch the jack uses There are four different switches that have been used with straight acting or fixed style jacks not counting the three wire switches that will be discussed later 2 8 2 1 The side port switch was a single wire switch and as named screws into the side of the jack cylinder The switch has a spring that isolates two contacts when the jack is retracted As the rod retracts into the barrel the top of the rod hits the end of the switch pushing the spring and end contact up When the cylinder extends about inch the spring pulls the two contacts together supplying a ground from the body of the switch to the wire of the switch The switch is a normally closed switch with the spring in the relaxed position The switch wire should have a single pin Packard connector The pivot point of a straight acting jack with this switch can be a weak point for the ground circuit due to dirt or corrosion Attaching a hose clamp wire assembly to the jack cylinder and directly to the frame can help if this problem arises Allow enough slack in the wire for the jack to pivot without putting a strain on the wire Make all connections watertight to maintain a good ground 12 Changing this switch will be difficult if the existing sw
123. the wire 2 Strip 1 8 inch of insulation from the wire 3 Choose the appropriate wire crimp position on the tool 4 Position the wire crimp barrel in the crimping tool and close the handles just enough to hold the contact in place Make sure the crimp wings are centered 5 Insert the bare wire into the wire crimp barrel of the contact and squeeze the handles together Remove the contact from the crimp tool and gently try to pull the wire from the contact to check the crimp 6 Position the small end of the wire seal onto the wire seal crimp wings 7 Reposition the contact in the crimp tool with the wire seal crimp wings centered in the crimp marked INS Pull the handles of the tool together 8 Remove the wire and contact assembly from the tool and visually inspect both crimps Do not try to pull the wire seal from the crimp AMP UML CRIMPTOOL a ANP he CHAMP FT 18 i Ger 1 sure DO o OO VA Sage NS A ba al Ne 22 1 o WIRE SEAL BARE WIRE WIRE SEAL H CRIMP WINGS gt CRIMP WINGS 4 lt 111 7 PIN WIRE AND PIN ASSEMBLY Fig 59 Contact and connector assembly for EJS connectors The pin contact is used with the plug and the socket contact is used with th
124. tinuity between the wires of the switch With air exhausting from the manifold and the air seal fully deflated this is a visual check the contacts of the switch should close completing a ground circuit It may take several seconds after the air seal is fully deflated to activate the vacuum switch Not all air seal manifolds will have a vacuum switch 2 11 SOLENOID VALVES HYDRAULIC AND AIR Solenoid valves are used to direct the flow of fluid or air in our leveling systems and slide mechanisms Solenoid valves consist of some type of seat and an electric coil When the coil is energized the seat is activated to open or close depending on the type of valve When the coil is de energized a spring moves the seat back to its normal off position All valves except one hydraulic valve are controlled by switching the voltage side of the circuit HWH manufactures all of the hydraulic valves that used but none of the air valves We will discuss the different types of hydraulic and air valves separately We will then discuss the diagnostics of the valves jointly 2 11 1 Air solenoid valves We presently use seven different style air valves but there are multiple part numbers for some of these basic valves The difference in the valves is the wire connections for the valve All of our air valves are two wire valves One valve may have a ring terminal on one wire and a Packard connector on the other A different part number valve that uses the same basic v
125. to a too detailed explanation of how a motor works so here is the condensed version When current is applied to the armature and the field windings it creates two opposing magnetic fields Like fields repel and unlike fields attract This is what makes the motor turn As the armature revolves the current flow through the armature is reversed every half turn between the brushes and the commutator This is what keeps the motor turning As I said this is a very condensed explanation of how a motor works There are many good books that will give detailed discussions about magnetism and motors if you are inclined to gain that knowledge Be prepared for some in depth thought What we will focus on is the fact that what is needed to make the pump motor function is voltage and ground Again without getting into great detail here are some basic things to remember about the pump motors 1 When first turned on there will be a large inrush of current to start the motor turning This can create a momentary voltage drop on the pump motor circuit 2 The current draw of the motor will increase as the load on the motor increases As the hydraulic pressure in the system increases resistance to the pump gears turning increases This increases the load on the pump motor 3 Cable size is very important for proper system operation Too small a cable gauge diameter will cause an unacceptable voltage drop This can cause erratic system operation o
126. to test a connection is with a voltmeter The relays must be on and the pump motor should be running This method can be used to test any connection as long as the load for that connection is on Put one lead of the meter on the relay post and the other lead on the wire terminal The meter should show zero voltage Any voltage reading would indicate an unwanted resistance at the connection Finally there should be zero voltage drop between the input and output posts of a relay GOOD RELAY POST WEAK CONNECTION WIRE CONNECTION Tail VOLTAGE VOLTAGE TO FROM BATTERY PUMP RELAY PUMP MOTOR MOTOR RUNNING VOLTMETER VOLTMETER Fig 5 Connections can also be tested by comparing the voltage at the post to the voltage at the wire terminal The voltage should be the same when the exact same ground point is used to check the voltage The main ground point for the system should be used when testing connections this way The load needs to be running for this test procedure also Normally open NO relay diagnostics If the relay will not turn on close the contacts the following tests should be made These tests are made with the relay on This is where a test light will give you the basic answers you are looking for is always a good idea to check your test light with a known good voltage and ground source to verify that your test light is working I speak from experienc
127. troubleshooting a transistor It is necessary to understand what a transistor is and the basics of what it does when it becomes necessary to read a schematic NPN TYPE PNP TYPE EMITTER COLLECTOR EMITTER COLLECTOR BASE BASE Fig 10 In comparison to a relay the base of a transistor along with the emitter is the coil and the emitter and collector are the contacts The two types of transistors are the PNP and the NPN The PNP transistor uses a ground to switch the base and the NPN uses a positive voltage to switch the base When the base sees the switching signal current can then flow through the transistor between the emitter and collector The transistor symbol shows which way the current flows always in the direction of the arrow 2 7 CONTROL BOXES AND PANELS are the heart of HWH electrical systems They can be very simple like the 100 110 system panels or very complex like the 2000 series CAN systems Most systems will have one control box or panel but systems like the Active Air system or the 2000 series systems can have several different control boxes A 110 panel has one small pc board on it but a 680 control box may have as many as 8 different pc boards in it These pc boards can be very simple or very complex For example the 110 pc board has 11 resistors 5 diodes 1 transistor and 10 LEDs That s not very many components considering you need 1 resistor for each LED And that pc board controls the whole system I m not going to eve
128. ture 4 Relative mode Everything has resistance even the meter probes The Relative Mode compensates for the probe resistance to give you an accurate reading when measuring resistance You simply hold the probes together and push the REL button This will 0 out the meter 5 Adaptability Will the meter accept and have available accessories such as alternate style probes clamp on amp meter or a temperature probe 6 Price 3 2 2 Digital multimeter functions Most digital multimeters will have the same standard functions The more expensive the meter the more functions the meter may have In this section we will concentrate on the standard functions as these are the functions you will need when diagnosing HWH equipment These are the symbols that will be on the meter selector dial This is for measuring Volts AC Alternating Current Normally you will not need this scale but we have done a few 110 volt pieces of equipment lt V This is for measuring Volts DC Direct Current The will be the main scale that you will use This is for measuring Milli Volts DC This scale reads thousandths of a volt If mV is preceded by a number such as 300 that means this scale will read up to 300 of a volt To read a greater voltage you have to go to the V scale Q This is for measuring resistance or ohms Most meters will have multiple ranges These ranges are 63 Up to 999 ohms depending on the meter KQ Up to 999 999 ohms depending
129. valve is bad no matter what resistance the coil is producing If a valve drops out at 4 4 volts the valve is bad Again the resistance does not matter Sometimes the easiest test to do on a coil is just check continuity between the two sides of the coil If there is no continuity the coil is bad Components with coils can also be affected by the length of time they are on The wire used to make coils is insulated This insulation can deteriorate under an excessive heat situation The longer a coil is on the more heat can be generated This depends on the design of the coil If one of our small valves is on over 20 minutes the coil can start to deteriorate and damage the valve The relays we use for our master relay or the valves we use for our air leveling systems can be on for hours without damage If the coil wire deteriorates enough this can create a short or an open spot in the coil A coil with a short will usually blow the fuse that protects that circuit If there is no fuse or the fuse does not blow the wires or other components in the circuit can be damaged If there is an open spot in the coil the component simply will not work The coil will show no continuity between the two ends of the coil Finally when the coil is turned off it will discharge a large amount of voltage This discharge can cause damage to the switch By placing a diode in line with the coil this will allow the voltage to dissipate through the coil instead of through th
130. witch even the Hall Effect switch should be simple Another important thing to consider when diagnosing limit switch problems is the adjustment of the switch A large percentage of the time the switch problem will turn out to be an adjustment problem Make sure the magnet and switch are positioned properly If the switch is a mechanical switch the switch arm or the switch activating cam may need to be adjusted It is also very important to make sure the room floor lock or seal are actually in the correct position for the switch to read Rooms especially with locks will have a sequence that must happen for the room to operate properly Sometimes the sequence involves the 3000 psi pressure switch with a limit switch before the sequence can continue The problem may not always be the limit switch Mechanical and magnetic limit switches These switches are like any switch If the switch has normally open contacts there should be no continuity from one side of the switch to the other when the switch is not activated If the switch has normally closed contacts there should be continuity between the contacts with very little resistance when the switch is not activated The position of the switch contacts should change when the switch is activated Example 1 The switch is a magnetic room position switch to detect when the room is retracted The switch is a normally open switch The switch completes a ground circuit As the room is retracting there should
131. y closed circuit and one normally open circuit Relays are also designed according to the frequency the contacts are operated There are continuous duty relays These relays can be on for long periods of time without causing damage to the relay but should not be turned off and on rapidly in a short period of time There are intermittent duty relays These relays are designed to be cycled off and on while being used It is important that the correct relay is used and although they look similar one relay maybe continuous duty and the other intermittent duty Our relays should not be confused with the Ford starter relay or other relays of that type 3 RELAY CONTACTS e pa NO REENE A COIL A E Fig 3 EE We use relays for many different purposes We use them to switch large amounts of current that a manual switch or a computer processor will not handle They are used to send information to computer processors from limit switches or warning switches They can also be used as a safety switch to interrupt a process that is reaching a critical condition that could create a system or component failure Many of the relays we use are pc board mounted and are not field serviceable The main relays we use that are serviceable are on the hydraulic pump motors and on our air compressor assemblies There are two different types of relays used on the hydraulic pump motors a
132. ync cylinder for each room cylinder Each switch is a normally open switch and completes a ground circuit when the contacts of the switch close as the pressure between the sync cylinder and a room cylinder reaches 5000 4000 psi This switch is important because if a four cylinder room extension cylinder jams during a cylinder retract procedure the pressure between the sync cylinder and the jammed cylinder can exceed 10 000 psi This will certainly damage cylinders and hoses If the pressure reaches 5000 4000 psi the sync cylinder pressure switch contacts close This opens a Bosch relay on the pump motor and turns the pump motor off Never operate any four cylinder room extension if any one of the four 5000 4000 psi sync cylinder pressure switches are unplugged 2 9 5 Air compressor air pressure switch The air compressor pressure switch is a normally closed two wire information or control switch This is the only pressure switch used by HWH to switch a positive voltage This switch is used to keep the compressor off unless the vehicle system pressure drops below a specific level There have been several different switches that are or have been used One of the switches is a set pressure that cannot be changed and the other switch is an adjustable switch It is also the only switch that the hysteresis of the switch is considered important Hysteresis is the difference in pressure where the switch contacts open and close This will be explained in detail
133. ys are still available but if not the present relays can be adapted to any system produced by HWH Pump or Master Relay Bosch Relay SIDE VIEW FRONT VIEW SIDE VIEW BOTTOM VIEW tt 85 87a 87 2 q Hi Fig 2 A relay consists of an electrical coil and a set of contacts The coil is used to produce a magnetic field that moves the contacts The coil of a relay is designed to work with a specific amount of voltage If an incorrect amount of voltage is used to operate a relay the relay will probably malfunction The coil of the relay will burn out it the voltage is too high or will not function if the voltage is too low The contacts of a relay have limitations The contacts will have a maximum amount of voltage and current they can withstand without damaging the contacts All of the relays we use are non directional and the contacts can be used to switch voltage or ground Either terminal for the relay contacts could be the supply side or the output side The relay coils are also non directional There is no diode installed on the coil of the relays we use Either terminal for the relay coil could be the voltage or the ground for the coil A relay can have normally open contacts normally closed contacts or both Some relays can be wired to operate as normally open or normally closed A relay of this type could be used to control two different circuits one normall

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