BENDIX BW1959 User's Manual
Contents
1. ROUBLESHOOTING If the status light remains on inspect the EC 12 for illuminated LEDs If no status light was installed the diagnostic LEDs should be checked periodically Reset controller with magnet after repair CHECK THE VEHICLE WIRING HARNESS CONNECTOR IF THESE LED S FOR THE PROPER RESISTANCE WITH MC 12 Controller Cable Assembly ANELEE AA AEU STOP LAMP POWER OFF To Controller l M a a Ml a T A Stop Lamp Power Stop Lamp Power B Constant Power Constant Power C In Cab Status Lamp Ground D Trailer Status Lamp Trailer Status Lamp SENSOR 1 E Ground Cab Status Lamp optional PNMLKJH GFEDCBA Sensor 2 yellow Ee a Sensor 2 yellow Sensor 1 N m P 15 2500 Ohms A Sensor 1 ii Sensor 1 blue i Sensor 1 blue Vehicle wire harness SENSOR 2 Most Commonly Encountered Problems That Result In LEDs Being Illuminated PNMLKJH GFEDCBA Repair or Replacement Components As Necessary L M 15 2500 Ohms e Damaged connectors or wires caused by dangling or loose wires not properly restrained e Power connection not capable of supplying 12 volts at 3 amps because of a poor connection bad crimp e Corroded connectors and connections not properly sealed or seated e Terminals not completely latched or sealed into connectors harness connector bolt not tight e Improperly spliced connection repair or repair not sealed properly e Excessive sensor air gap sensor bushing tension or excessive bearing end play MODULATOR Gently push sen2. Troubleshooting The Bendix MC 12 Trailer AntiLock System Post 2 98 STATUS INDICATOR 7 PINCONNECTOR Ground Back Constant Power Stop Lamp Power Constant Power Stop Light In Cab Status Light Trailer Status Light Ground lt vapi ANTILOCK Bendix INDICATOR MC 12 Modulator Controller IF INDICATOR REMAINS ILLUMINATED SYSTEM REQUIRES SERVICE Ref SD 1 3 4762 WHEEL SPEED SENSOR CONNECTOR Resistance Across Pins Zp 1500 2500 ohms IE Ref SD 13 4754 Wheel Speed 7 f Sensor RZ S SRL TYPICAL TRAILER AXLE OPERATIONAL INFORMATION The EC 12 controller houses the electronics that regulate the antilock system The EC 12 contains a diagnostic window and a 14 pin connector Diagnostic Window The EC 12 mounts on the M 12 modulator with four bolts and it is internally connected to the solenoids by a four pin connector Sensors mounted at the wheel end send wheel speed information to the EC 12 through the 14 pin connector If wheel lock up is impending the EC 12 commands the solenoids to modulate brake chamber pressure on the axle s in which the system is installed The MC 12 modulator controller receives power and ground from the vehicles electrical system During start up trailer antilock immediately runs a self check The trailer status light flashes once and then goes off Should a problem occur the status light comes on and remains on T
3. sor against exciter ring or readjust bearings e Non functioning antilock components sensor controller modulator Additional Servicing Tips e Do not pierce wires with probes when troubleshooting harnesses e Gently probe terminals when checking for resistances do not deform contacts e Apply nonconductive dielectric grease to any and all VOLTAGE connectors if inspecting or disconnecting connectors w STOP e If excessive cable length is present bundle and LAMP tie wrap neatly to adjacent air lines or POWER PNMLKJH GFEDCBA framing members A C 9to 18 Volts DC B C 9to 18 Volts DC ECU CONTROLLER Replace Controller ADDITIONAL INFORMATION 1 800 247 2725 2 1 All CONTACT OF THE 14 PINCONNECTOR ABOVE SHOULD NOT HAVE ANY CONTINUITY Visit www bendix com TO THE GROUND CONTACT C CONTACTS A amp B ARE POWER TO THE MC 12 BW1959 Bendix Commercial Vehicl Systems LLC 2 2000 e Printed in USA e All Rights Reserved
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