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14

Troubleshooting

SECTION IV

TESTING FOR POWER TO THE EC-12

 CONTROLLER

TURN IGNITION OFF, 

 

DISCONNECT 14 PIN

WIRE HARNESS CONNECTOR FROM EC-12

CONTROLLER

START HERE

VOLTAGE SAME AS BATTERY

VOLTAGE?  MUST BE

BETWEEN 8 AND 17 VOLTS.

RECONNECT  CONNECTOR TO EC-12

CONTROLLER.  CHECK THE VEHICLE

WIRING FOR CONTINUITY.  REFER TO THE

VEHICLE SERVICE MANUAL AND CHECK

THE BATTERY VOLTAGE.  REPAIR OR

REPLACE AS NECESSARY AND REPEAT

THE "INITIAL START-UP PROCEDURE"

YES

NO

MAGNET HERE

PERFORM A MAGNETIC RESET BY

PASSING A MAGNET OVER THE

"RESET" IN EC-12

 CONTROLLER

DIAGNOSTIC WINDOW THEN

REMOVE MAGNET

TURN IGNITION 

OFF, 

(DO NOT APPLY BRAKES)

RECONNECT WIRE HARNESS TO EC-12

 CONTROLLER.

TURN IGNITION 

ON

 & APPLY & HOLD BRAKES ON.

IS THE RED, "VOLT" LED

STILL ILLUMINATED?

TURN IGNITION ON, MAKE & HOLD A BRAKE

APPLICATION AND, MEASURE  VOLTAGE

BETWEEN  POWER AND  GROUND PINS ON

WIRE HARNESS CONNECTOR

A to C

B to C

RESETTING

EC-12

CONTROLLER

CHECKING "VOLT"

LED

ON?

ON ?

REPLACE EC-12

CONTROLLER

REPEAT THE

“INITIAL START-UP

PROCEDURE”.

YES

NO

A B C D E F G

 H J K L M N P

POWER A & B

GROUND C

EC-12

 CONTROLLER

WIRE HARNESS CONNECTOR

Summary of Contents for MC-12 MODULATOR CONTROLLER ASSY

Page 1: ...pin A and optionally pin B from the auxiliary terminal blue wire of the trailer s 7 pin connector DESCRIPTION The Bendix MC 12 modulator trailer antilock system is designed to improve vehicle stabilit...

Page 2: ...ht 14 16 14 16 14 16 10 11 N P Wheel Speed Sensor 16 18 16 18 16 18 12 13 M L Wheel Speed Sensor 16 18 16 18 16 18 Antilock Connector Pin B is an option and is used to provide constant power to the MC...

Page 3: ...s on and remains on when the trailer brakes are actuated a system problem has occurred The EC 12 controller contains a diagnostic window which FIGURE 3 SPEED SENSOR VOLTAGE CYCLE OUTPUT PEAK TO PEAK P...

Page 4: ...lock system to alter the service brake application When activated shuttles within the solenoids alter the application and exhaust of control air pressure The supply solenoidcloses preventingcontrollin...

Page 5: ...ACTIVATED EXHAUST SUPPLY EXHAUST SOLENOID CONTROL DOUBLE CHECK TRAILER CONTROL BRAKE VALVE DELIVERY PISTON SUPPLY SOLENOID SERVICE BRAKE CHAMBER DELIVERY PISTON EXHAUST SUPPLY EXHAUST SOLENOID CONTRO...

Page 6: ...injury resulting from contact with moving rotating leaking heated or electrically charged components 3 Do not attempt to install remove disassemble or assemble a component until you have read and tho...

Page 7: ...ve the EC 12 controller 1 from the M 12 modulator by removing the controller s four mounting bolts 2 Lift the controller off the M 12 modulator and detach the wire harness from the base of the control...

Page 8: ...controller onto the solenoid assembly and secure with the four 1 2 bolts and lock washers Torque to 30 60 in Ibs OPERATIONAL AND LEAKAGE TEST 1 Chock wheels Fully charge air brake system and adjust br...

Page 9: ...HE TRAILER WHILE PERFORMINGTHE INITIALSTART UPPROCEDURE and following the directions contained in the procedure Be sure to record a failure before resetting the system Reset by holding a magnet capabl...

Page 10: ...DTO TRACTOR TURNIGNITIONON APPLY TRAILERSERVICEBRAKESAND OBSERVESTATUSLAMPMOUNTED ONTRAILER NO DID STATUS LAMP ILLUMINATE GO TO SECTION I STATUS LAMP TESTING ARE STOP LAMPS ILLUMINATED YES TEST FOR PO...

Page 11: ...RDER PRESENTED AND AFTER REPLACING OR TESTING EACH COMPONENT TEST THE STATUS LAMP OPERATION 1 CHANGE TRAILER STATUS LAMP BULB 2 CHECK TRAILER STATUS LAMP WIRING GROUND 3 CHECK CONTINUITY OF WARNING WI...

Page 12: ...NO ARE ANY RED LED s ILLUMINATED YES NO YES GOTOSECTIONIV TESTINGFORPOWER TOTHEEC 12 CONTROLLER NOTE AND RECORD THE CONDITION OF ALL RED LEDS GO TO SECTION III INSPECTION FOR ILLUMINATED LEDS RED LEDs...

Page 13: ...S1 OR SNS2 LED ILLUMINATED IS RED MOD LED ILLUMINATED YES NO TESTING MOD LED IFANYOTHERREDLEDs AREILLUMINATED REPLACETHEEC 12 CONTROLLERANDREPEAT THE INITIALSTART UP PROCEDURE GO TO SECTION V TESTING...

Page 14: ...URE YES NO MAGNET HERE PERFORMAMAGNETICRESETBY PASSINGAMAGNETOVERTHE RESET INEC 12 CONTROLLER DIAGNOSTICWINDOWTHEN REMOVEMAGNET TURNIGNITIONOFF DONOTAPPLYBRAKES RECONNECTWIREHARNESSTOEC 12 CONTROLLER...

Page 15: ...RETURNED TOTHISSTEP TWICE REPLACETHE EC 12 CONTROLLER REPLACEEC 12 CONTROLLER NO GO TO SECTION III INSPECTION FOR ILLUMINATEDLEDS AND RETEST IFFAILUREPERSISTS REPLACETHEEC 12 CONTROLLER WHITE BLACK WH...

Page 16: ...N P RESISTANCE FORBENDIX WS 20 SPEEDSENSORSHOULDBEBETWEEN1500 2500 OHMS REFERTOVEHICLEMAINTENANCEMANUALIFOTHERTHANTHE WS 20 SPEEDSENSORISINUSE IFRESISTANCE NOTCORRECT DISCONNECTCONNECTORATSPEEDSENSOR...

Page 17: ...INSPEC TION FOR ILLUMINATED LED s SAME LED s ILLUMINATED NO YES RECONNECTCONNECTORATSPEED SENSORANDEC 12 CONTROLLER PASSMAGNETOVER RESET ONEC 12 CONTROLLER REMOVEMAGNETAND OBSERVELEDs IGNITIONOFFSERV...

Page 18: ...PWR LED green EC 12 Controller Power TRAILER MOUNTED STATUS LAMP POWER FROM STOPLIGHTS GROUND 7PIN TRAILER ELECTRICAL CONNECTOR CONSTANT POWER FROM TRACTOR IGNITION OPTIONAL CONNECTION GROUND A B C D...

Page 19: ...19 NOTES REFERENCES...

Page 20: ...BW1667 2004 Bendix Commercial Vehicle Systems LLC All rights reserved 4 2004 Printed in U S A...

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