GMC Forward Control P3500 (1985-1999) brn Wiring diagrams

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID A/T ISS HI IN A/T ISS LO IN AUTO TRANSMISSION INPUT SHAFT SPEED SENSOR (INSIDE FRONT OF TRANSMISSION) AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BRAKE SWITCH INPUT BRN WIRE BRN/WHT WIRE DATA CLASS II DK BLU WIRE DK BLU/WHT WIRE ECM BATT FUSE ECM I FUSE ECT SENS INPUT ENG 1 FUSE ENGINE COOLANT TEMP SENSOR (TOP FRONT OF ENGINE) FUSE GAUGES FUSE GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION INDICATOR LAMP MIL CONTROL ORG/ WIRE PCM GROUND PCS SOL HI OUT PCS SOL LO OUT PNK WIRE PPL PPL DATA LINK CONNECTOR PPL/WHT WIRE PRESS CTRL SOLENOID RANGE SIGNAL "A" RANGE SIGNAL "B" RANGE SIGNAL "C" RED WIRE RED/BLK WIRE SENSOR GROUND SENSOR RETURN TCC PWM SOL TCC PWM SOLENOID TCC/STOP- LAMP SWITCH (ON BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (MOUNTED TO SIDE OF THROTTLE BODY) TP SENS INPUT TRANS FLUID TEMP SENSOR TRANS FUSE TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANS TEMP SIG IN VEHICLE CONTROL MODULE (VCM) (BEHIND LEFT HEADLIGHT) VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION) VSS HI VSS LO YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID A/T ISS HI IN A/T ISS LO IN AUTO TRANSMISSION INPUT SHAFT SPEED SENSOR (INSIDE FRONT OF TRANSMISSION) AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BRAKE SWITCH INPUT BRN WIRE BRN/WHT WIRE DATA CLASS II DK BLU WIRE DK BLU/WHT WIRE ECM BATT FUSE ECM I FUSE ECT SENS INPUT ENG 1 FUSE ENGINE COOLANT TEMP SENSOR (TOP FRONT OF ENGINE) FUSE GAUGES FUSE GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION INDICATOR LAMP MIL CONTROL ORG/ WIRE PCM GROUND PCS SOL HI OUT PCS SOL LO OUT PNK WIRE PPL PPL DATA LINK CONNECTOR PPL/WHT WIRE PRESS CTRL SOLENOID RANGE SIGNAL "A" RANGE SIGNAL "B" RANGE SIGNAL "C" RED WIRE RED/BLK WIRE SENSOR GROUND SENSOR RETURN TCC PWM SOL TCC PWM SOLENOID TCC/STOP- LAMP SWITCH (ON BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (MOUNTED TO SIDE OF THROTTLE BODY) TP SENS INPUT TRANS FLUID TEMP SENSOR TRANS FUSE TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANS TEMP SIG IN VEHICLE CONTROL MODULE (VCM) (BEHIND LEFT HEADLIGHT) VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION) VSS HI VSS LO YEL WIRE YEL/BLK WIRE

A/C COMPRESSOR CONTROL RELAY (RIGHT SIDE OF DRIVER'S ISLAND) A/C COMPRESSOR HIGH PRESSURE CUTOFF SWITCH (IN HIGH PRESSURE LINE) A/C COMPRESSOR REFRIGERANT PRESSURE SWITCH (REAR OF A/C COMPRESSOR) A/C ENABLE BLK WIRE BRN WIRE DIODE A/C COMPRESSOR CLUTCH DK GRN WIRE DK GRN/WHT WIRE ENG-BAT FUSE GAUGES FUSE GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN RUN I/P FUSE BLOCK ORG/ WIRE PNK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF DRIVER'S ISLAND) A/C REQUEST WHT WIRE

A/C COMPRESSOR CLUTCH RELAY (RIGHT SIDE OF DRIVER'S ISLAND) A/C COMPRESSOR HIGH PRESSURE CUTOFF SWITCH (REAR OF A/C COMPRESSOR) A/C COMPRESSOR REFRIGERANT PRESSURE SWITCH (A/C ACCUMULATOR) A/C ENABLE A/C GROUND A/C REQUEST BLK WIRE BRN WIRE DIODE A/C COMPRESSOR CLUTCH DK GRN WIRE DK GRN/WHT WIRE ENG-BAT FUSE GAUGES FUSE GRN WIRE HOT AT ALL TIMES HOT IN RUN I/P FUSE BLOCK ORG/ WIRE PNK WIRE VEHICLE CONTROL MODULE (CENTER FRONT OF ENGINE COMPT) WHT WIRE

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID A/T ISS HI IN A/T ISS LO IN AUTO TRANSMISSION INPUT SHAFT SPEED SENSOR (INSIDE FRONT OF TRANSMISSION) AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BRAKE SWITCH INPUT BRN WIRE BRN/WHT WIRE DATA CLASS II DK BLU WIRE DK BLU/WHT WIRE ECM BATT FUSE ECM I FUSE ECT SENS INPUT ENG 1 FUSE ENGINE COOLANT TEMP SENSOR (TOP FRONT OF ENGINE) FUSE GAUGES FUSE GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION INDICATOR LAMP MIL CONTROL ORG/ WIRE PCM GROUND PCS SOL HI OUT PCS SOL LO OUT PNK WIRE PPL PPL DATA LINK CONNECTOR PPL/WHT WIRE PRESS CTRL SOLENOID RANGE SIGNAL "A" RANGE SIGNAL "B" RANGE SIGNAL "C" RED WIRE RED/BLK WIRE SENSOR GROUND SENSOR RETURN TCC PWM SOL TCC PWM SOLENOID TCC/STOP- LAMP SWITCH (ON BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (MOUNTED TO SIDE OF THROTTLE BODY) TP SENS INPUT TRANS FLUID TEMP SENSOR TRANS FUSE TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANS TEMP SIG IN VEHICLE CONTROL MODULE (VCM) (BEHIND LEFT HEADLIGHT) VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION) VSS HI VSS LO YEL WIRE YEL/BLK WIRE

A/C COMPRESSOR CLUTCH RELAY (RIGHT SIDE OF DRIVER'S ISLAND) A/C COMPRESSOR HIGH PRESSURE CUTOFF SWITCH (REAR OF COMPRESSOR) A/C COMPRESSOR REFRIGERANT PRESSURE SWITCH (REAR OF COMPRESSOR) BLK WIRE BRN WIRE DIODE A/C COMPRESSOR CLUTCH DK GRN WIRE ENG-BAT FUSE GRN WIRE GRY WIRE HOT AT ALL TIMES I/P FUSE BOX ORG/ WIRE

1-3 FUSE 9 12 2 DATA LINK CONNECTOR (BELOW DASH, NEAR STEERING COLUMN) PPL ABS IND. BATTERY GROUND BLK (OR BLK/WHT) WIRE BLK WIRE BRAKE IND BRAKE PRESSURE DIFFERENTIAL SWITCH (INTERNAL TO ELECTRONIC BRAKE CONTROL MODULE) BRN WIRE DIESEL DIESEL: ENGINE HARN, 32 CM FROM BREAKOUT TO BATTERY JUNCTION BLOCK) DIODE NETWORK (ON I/P HARNESS, BODY BUILDER INSTALLED) DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE (BELOW RADIATOR, ON LOWER CROSSMEMBER) FUSE LINK (IN BATTERY JUNCTION BLOCK, AT LEFT REAR OF ENGINE COMPT) GAS GAS DIESEL GAUGES FUSE 8 HOT AT ALL TIMES HOT IN RUN HOT IN RUN AND START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) IGNITION ABS LAMP CONTROL BRAKE SW INPUT INSTRUMENT CLUSTER LEFT FRONT WHEEL SPEED SENSOR LT BLU WIRE LT GRN WIRE NCA WIRE PNK WIRE PPL PPL PPL 1807 680 RED WIRE RIGHT FRONT WHEEL SPEED SENSOR SENSOR LOW SENSOR LOW SENSOR HIGH SENSOR HIGH 873 833 STOPLAMPS SWITCH (AT BRAKE PEDAL SUPPORT) TAN WIRE TAN/WHT WIRE VEHICLE SPEED SENSOR CALIBRATOR (LEFT SIDE OF DRIVER'S ISLAND ON RELAY BRACKET) WARNINGS SYSTEM YEL WIRE YEL/BLK WIRE

ABS IND. BLK WIRE BLK/ WHT WIRE BRAKE IND BRAKE PRESSURE DIFFERENTIAL SWITCH BRAKE/ BRN WIRE DIESEL GASOLINE DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE (BELOW RADIATOR OF FIRST CROSSMEMBER) FUSIBLE LINK HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START GAUGES FUSE I-3 FUSE I/P FUSE BLOCK IGN ABS LAMP CONTROL BRAKE SW INPUT INSTRUMENT CLUSTER LEFT FRONT WHEEL SPEED SENSOR LFT FRT SENSOR (-) LT BLU WIRE LT GRN WIRE PNK WIRE PPL PPL PPL PUMP MOTOR POWER PUMP MOTOR GROUND RED WIRE RIGHT FRONT WHEEL SPEED SENSOR RT FRT SENSOR (-) LFT FRT SENSOR (+) RT FRT SENSOR (+) TAN WIRE TAN/WHT WIRE TCC/ STOPLAMP SWITCH UNDERHOOD FUSE-RELAY CENTER VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SIG VSS BUFFER (LEFT SIDE OF INTERIOR BULKHEAD) VSS SIG SERIAL DATA LINE SERIAL DATA SIGNAL BRAKE LAMP CONTROL EBCM GROUND WHT WIRE YEL WIRE YEL/BLK WIRE

A/T BRN WIRE HOT IN RUN I/P FUSE BLOCK LEFT BACKUP LAMP LT GRN WIRE M/T PARK/NEUTRAL POSITION (PNP), BACKUP LAMP SWITCH (LEFT SIDE OF TRANSMISSION) RIGHT BACKUP LAMP TURN B/U FUSE 5 TURN SIGNAL FLASHER

1996-97 1998/ 1999 92 PPL (OR 94 PNK WIRE BLK WIRE BRN WIRE BRN/WHT WIRE DELAY RHEO- STAT GRY WIRE HIGH OFF LOW OFF WASH PULSE HOT IN ACCY AND RUN I/P FUSE BLOCK LT BLU WIRE LT BLU/BLK WIRE LT GRN/BLK WIRE MIST PNK 94 WIRE PPL 92 PROVISIONS FOR WIPER/WASHER MOTOR PULSE WIPER CONTROL MODULE (STRAPPED TO HARNESS UNDER DRIVER'S ISLAND) WIPER FUSE WIPER FUSE 14 WIPER/ WASHER SWITCH YEL WIRE