GMC Forward Control P3500 (1985-1999) lt grn/blk 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

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

1996 VFTC ACCY BLK WIRE BLK/WHT WIRE BULB TEST DAYTIME RUNNING LAMPS (DRL) MODULE (ATTACHED TO I/P HARNESS AT STEERING COLUMN) DAYTIME RUNNING LAMPS (DRL) RELAY (ON MAIN SUPPORT BRACKET AT DRIVER'S ISLAND) DAYTIME RUNNING LAMPS (DRL) RELAY 2 DIODE NETWORK DK BLU WIRE DK GRN/WHT WIRE DRL INDICATOR GAUGES FUSE GRN WIRE HEAD- LAMP DIMMER SWITCH HEADLAMPS SWITCH HI BEAM INDICATOR HI LO HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK IGNITION SWITCH INSTRUMENT CLUSTER INSTRUMENT CLUSTER SYSTEM LEFT HEAD- LAMP LEFT HI BEAM HEAD- LAMP LO HI LOCK OFF LT GRN WIRE LT GRN/BLK WIRE NEAR BREAKOUT FOR CHASSIS HARNESS) ORG/ WIRE PARK BRAKE IN FOG LAMPS PARK BRAKE INDICATOR SWITCH (ON PARK BRAKE) PARK HEAD OFF PNK IGNITION LAMP FEED HI BM FEED HI BM INDICATOR DRL RELAY CTRL GROUND WIRE PNK WIRE RIGHT HEAD- LAMP RIGHT HI BEAM HEAD- LAMP RUN WIRE TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE

BLK WIRE BLU WIRE BREAKOUT FOR HEADLAMP SWITCH) BULB TEST DAYTIME RUNNING LAMPS MODULE (ATTACHED TO I/P HARNESS AT STEERING COLUMN) DAYTIME RUNNING LAMPS RELAY (ON MAIN SUPPORT BRACKET AT DRIVER'S ISLAND) DAYTIME RUNNING LAMPS RELAY 2 DIODE NETWORK DK BLU WIRE DK GRN/WHT WIRE DRL INDICATOR FOR LEFT HEADLAMP) FUSIBLE LINK (16 GA- GAUGES FUSE GRN WIRE HEAD- LAMP DIMMER SWITCH HEADLAMPS SWITCH HI BEAM INDICATOR HI LO HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK IGNITION SWITCH INSTRUMENT CLUSTER INSTRUMENT CLUSTER SYSTEM LEFT HEAD- LAMP LEFT HIGH BEAM HEAD- LAMP LO HI LOCK OFF LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PARK BRAKE IN FOG LAMPS PARK BRAKE INDICATOR SWITCH (ON PARK BRAKE) PARK HEAD OFF PNK IGNITION LAMP FEED HI BM FEED HI BM INDICATOR RELAY OUT GROUND WIRE PNK WIRE RED WIRE RIGHT HEAD- LAMP RIGHT HIGH BEAM HEAD- LAMP RUN WIRE TAN WIRE WHT WIRE YEL WIRE

1996 VFTC ACCY BLK WIRE BLK/WHT WIRE BULB TEST DAYTIME RUNNING LAMPS (DRL) MODULE (ATTACHED TO I/P HARNESS AT STEERING COLUMN) DAYTIME RUNNING LAMPS (DRL) RELAY (ON MAIN SUPPORT BRACKET AT DRIVER'S ISLAND) DIODE NETWORK DK BLU WIRE DK GRN/WHT WIRE DRL INDICATOR GAUGES FUSE GRN WIRE HEAD- LAMP DIMMER SWITCH HEADLAMPS SWITCH HI LO HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK IGNITION SWITCH INSTRUMENT CLUSTER INSTRUMENT CLUSTER SYSTEM HI BEAM INDICATOR LEFT HEAD- LAMP LO HI LOCK OFF LT GRN WIRE LT GRN/BLK WIRE NEAR BREAKOUT FOR CHASSIS HARNESS) ORG/ WIRE PARK BRAKE IN FOG LAMPS PARK BRAKE INDICATOR SWITCH (ON PARK BRAKE) PARK HEAD OFF PNK IGNITION LAMP FEED HI BM FEED HI BM INDICATOR DRL RELAY CTRL GROUND WIRE PNK WIRE RIGHT HEAD- LAMP RUN WIRE TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE

4 13 PNK WIRE A/T ABS IND. ACCY BULB TEST LOCK OFF ANTI-LOCK BRAKES SYSTEM AUTO PARK IND. BLK WIRE BLK/WHT WIRE BRAKE IND DRL IND BRN/WHT WIRE CHECK GAUGES IND COOLANT TEMPERATURE GAUGE DIESEL DK BLU WIRE DK GRN WIRE DOOR AJAR IND ECM 1 FUSE 12 ENGINE CONTROLS OR STARTING/ CHARGING SYSTEM ENGINE CONTROLS SYSTEM ENGINE CONTROLS SYSTEM ENGINE CONTROLS SYSTEM ENGINE COOLANT LEVEL SWITCH (ON LOWER LEFT END OF RADIATOR SURGE TANK) FUEL GAUGE FUEL SENDER (ON TOP OF FUEL TANK) GAS GAUGES FUSE 8 GRY WIRE GRY/BLK WIRE HEADLIGHTS SYSTEM HI-BEAM IND HOT IN RUN OR START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) IGNITION SWITCH ILLUMINATION IN-LINE CONNECTOR PROVISIONS FOR BODY BUILDER INSTRUMENT CLUSTER INTERIOR LIGHTS SYSTEM WARNING SYSTEMS LEFT TURN IND LOW COOLANT IND LT BLU WIRE LT GRN (OR WHT) WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION IND. LAMP (MIL) (SERVICE ENGINE SOON IND) OIL PRESSURE GAUGE PNK WIRE PPL PPL DIESEL PPL GAS PPL RIGHT TURN IND RUN WIRE SEAT BELT IND SERVICE THROTTLE SOON IND SPEEDOMETER TACHOMETER TAN WIRE TAN/WHT WIRE VEHICLE CONTROL MODULE (ON LEFT SIDE OF RADIATOR SUPPORT) VOLTMETER VSS CALIBRATOR (LEFT SIDE OF DRIVER'S ISLAND, UNDER RELAY BRACKET) WAIT TO START IND WATER IN FUEL IND WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

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

1223 1222 SHIFT SOL B OUT SHIFT SOL A OUT HIGH IDLE SW OUT 3-2 CTRL OUT 1225 1226 419 RANGE MODE SEL B RANGE MODE SEL C SERV ENG SOON IND CTRL 465 1229 FUEL PMP RLY CTRL FORCE MOTOR HI 470 OR 452 496 1456 KNOCK SENS INPUT EGR INPUT A/T INPUT SPEED SENSOR (ON AUTO TRANSMISSION LEFT CENTER) BLK WIRE BLK/RED WIRE BLK/WHT WIRE BLU WIRE BREAKOUT FOR ENGINE COOLANT FAN MOTOR) BRN WIRE BRN/WHT WIRE BYPASS 5 VOLTS SENS GROUND SENS GROUND TRANS TEMP INPUT DIAG ENABLE-POWERTRAIN TP SENS IN DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECT SENS INPUT EGR SOL OUT ELECTRONIC 4-SPD AUTOMATIC OVERDRIVE TRANSMISSION EVAPORATIVE CANISTER PURGE SOLENOID (TOP LEFT CENTER OF INTAKE MANIFOLD) FUEL INJ CTRL GRN WIRE GRY WIRE HOT IN RUN, START (CRANK) I/P FUSE BLOCK (MOUNTED ON THE I/P) IDLE AIR CONTROL VALVE MOTOR (ON LEFT SIDE OF THROTTLE BODY INTAKE) KNOCK SENSOR (KS) (ON RIGHT SIDE OF ENGINE BLOCK AHEAD OF STARTER) LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE LT LT LT PNK PNK WIRE OIL PRESS INPUT MAP SENS INPUT ORG/ WIRE OXYGEN SENSOR (IN EXHAUST STREAM AHEAD OF MUFFLER) PCM GROUND PNK IGNITION CAN PURGE SOL OUT WIRE PNK PNK 26 27 WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) (ON LEFT SIDE OF DRIVER'S ISLAND) PPL PPL 16 17 18 19 PPL 420 474 BRAKE SW INPUT PPL/WHT WIRE RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SHIFT SOL. SHIFT SOL. SHIFT SOL. SHIFT SOL. FORCE MOTOR TAN WIRE TAN/BLK WIRE TRANS FUSE TRANS TEMP WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

4 7 8 9 11 12 13 15 VSS OUT VSS RETURN GROUND BLK WIRE BLK/RED WIRE BREAKOUT FOR ENGINE COOLANT FAN MOTOR, TOWARD CRUISE CONTROL MODULE) BRN WIRE BRN/WHT WIRE CONTACT CRUISE CONTROL MODULE (ON RADIATOR SUPPORT BRACKET) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM BAT FUSE ENG 1 FUSE ENGINE COOLANT TEMPERATURE SENSOR (FRONT, CENTER OF ENGINE COOLANT INTAKE) FROM BREAKOUT FOR CRUISE CONTROL MODULE, TOWARD ENG) FROM BREAKOUT FOR GENERATOR) GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN, START (CRANK) I-3 FUSE I/P FUSE BLOCK (MOUNTED ON THE I/P) IDLE SPEED CONTROL ACTUATOR (ON THROTTLE BODY) LEFT BULK- HEAD GROMMET UNDER I/P) LINEAR EGR SOLENOID VALVE (NO COMPONENT LOCATION AVAILABLE) LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK 9 10 11 12 13 14 15 16 WIRE PNK PNK 1 2 3 4 5 WIRE PNK PNK 26 27 WIRE PNK WIRE PPL PPL 16 17 18 19 PPL TCC/STOPLAMP INPUT PPL/WHT WIRE RED WIRE TAN WIRE TAN/BLK WIRE THROTTLE POSITION SENSOR (ON LEFT SIDE OF THROTTLE BODY) VEHICLE SPEED SENSOR (ON LEFT REAR SIDE OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (ON DRIVER'S ISLAND SUPPORT ABOVE ACCELERATOR PEDAL) VSS VSS LO VSS SIG VSS HI SECOND. VSS WHT WIRE YEL WIRE