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

2-3 SHIFT SOL BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRN WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN/BLK (OR DK GRN/YEL) WIRE ECM BAT FUSE ECM-CRNK FUSE ELECTRONIC 4-SPEED AUTOMATIC OVERDRIVE TRANSMISSION ENGINE COOLANT TEMP SENS (TOP RIGHT SIDE OF ENG) FUSE BLOCK TRANS FUSE GRY WIRE GRY/RED WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE ORG/ WIRE ORG/BLK (OR ORG) WIRE PNK WIRE PNK/BLK (OR BRN) WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF SHIPPING PANEL) PPL PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE TCC SOL 1-2 SHIFT SOL TCC/BRAKE SWITCH (ON BRAKE PEDAL SUPPORT ARM) THROTTLE POSITION SENSOR (TOP RIGHT SIDE OF ENG) TRANS- MISSION INPUT SPEED SENSOR (LEFT FRNT OF TRANS) TRANS- MISSION TEMP VEHICLE SPEED SENSOR (REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF I/P) WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

2-3 SHIFT SOL BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRN WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN/BLK (OR DK GRN/YEL) WIRE ECM BAT FUSE ECM-CRNK FUSE ELECTRONIC 4-SPEED AUTOMATIC OVERDRIVE TRANSMISSION ENGINE COOLANT TEMP SENS (TOP RIGHT SIDE OF ENG) FUSE BLOCK TRANS FUSE GRY WIRE GRY/RED WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE ORG/ WIRE ORG/BLK (OR ORG) WIRE PNK WIRE PNK/BLK (OR BRN) WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF SHIPPING PANEL) PPL PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE TCC SOL 1-2 SHIFT SOL TCC/BRAKE SWITCH (ON BRAKE PEDAL SUPPORT ARM) THROTTLE POSITION SENSOR (TOP RIGHT SIDE OF ENG) TRANS- MISSION INPUT SPEED SENSOR (LEFT FRNT OF TRANS) TRANS- MISSION TEMP VEHICLE SPEED SENSOR (REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF I/P) WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID 3-2 SHIFT SOL 3-2 SHIFT SOLENOID A/C COMPRESSOR RELAY, GENERATOR, TURBO CHARGER POWER VALVE A/T INPUT SPEED SENSOR (LEFT SIDE OF TRANSMISSION) A/T ISS SENS HI IN A/T ISS SENS LO IN ACCELERATOR PEDAL POSITION MODULE (ATTACHED TO ACCELERATOR PEDAL) APP 1 SIGNAL IN APP 2 SIGNAL IN APP 3 SIGNAL IN AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BRAKE SWITCH IN BRN WIRE BRN/WHT WIRE BUSS BAR CLASS II DATA DATA LINK CONNECTOR (PARTIAL) (BELOW DASH, NEAR STEERING COLUMN) DK BLU WIRE DK BLU/WHT WIRE DK GRN/WHT WIRE ECM 1 FUSE 12 ECM-BAT FUSE 6 ECT SENSOR IN ELECTRONIC BRAKE CONTROL MODULE ENGINE COOLANT TEMPERATURE SENSOR (TOP FRONT OF ENGINE) FUEL PUMP RELAY, FUEL PUMP SWITCH/ENGINE OIL PRESSURE INDICATOR SENSOR GAUGES FUSE 8 GRY WIRE HAZARD LAMPS FLASHER (ABOVE STEERING COLUMN) HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I-3 FUSE 9 I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MIL CONTROL ORG/ WIRE PCM GROUND PCS SOL HI OUT PCS SOL LO OUT PNK INSTRUMENT CLUSTER WIRE PNK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF DRIVER'S ISLAND) PPL PPL/WHT WIRE PRESS CTRL SOLENOID RED WIRE RED/BLK WIRE SENSOR GROUND SERVICE ENGINE SOON INDICATOR STOP-HAZ FUSE 11 STOPLAMP SWITCH IN TFT SENSOR IN TORQUE CONVERTER CLUTCH BRAKE, STOPLAMP SWITCH TRANS FLUID TEMP SENSOR TRANS RANGE "A" TRANS RANGE "B" TRANS RANGE "C" TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANSMISSION FUSE 17 TWISTED WIRE PAIR VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION) VEHICLE SPEED SENSOR CALIBRATOR (ABOVE ACCELERATOR PEDAL) VEHICLE SPEED SENSOR CALIBRATOR, ENGINE SHUTOFF SOLENOID VSS HI IN VSS LO IN VSS OUT YEL WIRE YEL/BLK WIRE

2-3 SHIFT SOL A/T INPUT SPEED SENSOR (LEFT SIDE OF TRANSMISSION) ANTI-LOCK BRAKES AUTOMATIC TRANSMISSION BLK WIRE BRN WIRE BRN/WHT WIRE BUSS BAR CRUISE CONTROL SYSTEMS DASH FUSE BLOCK DATA LINK CONNECTOR (PARTIAL) (BELOW DASH, NEAR STEERING COLUMN) DK BLU WIRE DK BLU/WHT WIRE ECM BAT FUSE ECM I FUSE ENGINE CONTROLS SYSTEMS ENGINE COOLANT TEMPERATURE SENSOR (TOP FRONT OF ENGINE) FUEL INJECTORS (ENGINE CONTROLS) FUEL PUMP RELAY GAUGES FUSE GRY WIRE GRY/RED WIRE HOT AT ALL TIMES HOT IN HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I-3 FUSE INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK IGNITION FEED WIRE PNK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF DASH) PPL PPL PNK WIRE PPL/WHT WIRE PRESSURE CONTROL SOL RANGE MODE SELECTOR RED WIRE RED/BLK WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR STOP LAMPS, TORQUE CONVERTER BRAKE SWITCH SWITCH TAN WIRE TCC PWM SOL 1-2 SHIFT SOL THROTTLE POSITION SENSOR (ON SIDE OF THROTTLE BODY) TRANS FLUID TEMP SENSOR TRANS FUSE VEHICLE SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (ABOVE ACCELERATOR PEDAL) WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

ABS IND. ACCY ACCY ANTI-LOCK BRAKES SYSTEM BLK WIRE BLK/WHT WIRE BRAKE IND BRAKE PRESSURE DIFFERENTIAL SWITCH (INTERNAL TO ELECTRONIC BRAKE CONROL MODULE) BRN/WHT WIRE CHECK GAUGES IND COOLANT TEMPERATURE GAUGE DIESEL DIODE NETWORK (DASH HARN, DK BLU WIRE DK GRN WIRE DOOR AJAR IND DRL IND ECM 1 FUSE 12 ELECTRONIC BRAKE CONTROL MODULE (EBCM) (BELOW RADIATOR, ON LOWER CROSSMEMBER) ENG 1 FUSE 15 ENGINE CONTROLS OR STARTING/CHARGING SYSTEM ENGINE CONTROLS SYSTEM ENGINE CONTROLS SYSTEM ENGINE CONTROLS SYSTEM TRANSMISSIONS SYSTEM ENGINE COOLANT LEVEL SWITCH (ON LOWER LEFT END OF RADIATOR SURGE TANK) FOOT BRAKE (PARK BRAKE APPLY OPPTION) FUEL GAUGE FUEL SENDER (ON TOP OF FUEL TANK) GAS GAUGES FUSE 8 GRY WIRE GRY/BLK WIRE HAND BRAKE HEADLIGHTS SYSTEM HI-BEAM IND HOT IN RUN OR START I/P FUSE BLOCK I/P FUSE BLOCK (BODY BUILDER INSTALLED) I/P FUSE BLOCK) INSTRUMENT CLUSTER IGNITION SWITCH ILLUMINATION IN-LINE CONNECTOR PROVISIONS FOR BODY BUILDER INTERIOR LIGHTS SYSTEM WARNING SYSTEMS LEFT TURN IND LOCK LOCK OFF OFF LOW COOLANT IND LT BLU WIRE LT BLU/BLK WIRE LT GRN (OR WHT) WIRE LT GRN WIRE MALFUNCTION IND (MIL) (SERVICE ENGINE SOON IND) NCA WIRE OIL PRESSURE GAUGE PNK 4 13 WIRE 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 TRANS IND. VEHICLE CONTROL MODULE (ON LEFT SIDE OF RADIATOR SUPPORT) VOLTMETER VSS CALIBRATOR (LEFT SIDE OF DRIVER'S ISLAND, UNDER RELAY BRACKET) W/ DRL W/O DRL WAIT TO START IND WATER IN FUEL IND WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

0.5 WATT) 1995 VFTC BLK WIRE BLK/YEL WIRE BRAKE IND BRAKE PRESSURE WARNING SWITCH (ON LEFT FRAME RAIL) IGNITION SWITCH BRAKE WARNING ALARM BUZZER (BEHIND LEFT SIDE OF I/P, NEAR FUSE BLOCK) BRN WIRE BRN/WHT WIRE COOLANT TEMP GAUGE CRUISE CONTROL SYSTEM DAYTIME RUNNING LAMPS IND DAYTIME RUNNING LAMPS MODULE (BEHIND LEFT SIDE OF I/P, ABOVE STEERING COLUMN) DAYTIME RUNNING LAMPS RELAY (BEHIND LEFT SIDE OF I/P, ABOVE STEERING COLUMN) DK BLU WIRE DK GRN WIRE DK GRN/YEL WIRE ELECTRONIC DELAY MODULE (BEHIND LEFT SIDE OF I/P, ON PARK BRAKE SUPPORT BRACKET) ENGINE CONTROLS SYSTEM FLOW SWITCH (NEAR POWER STEERING PUMP) FUEL GAUGE FUSE BLOCK GAGES FUSE GRY WIRE HEADLIGHTS SYSTEM HI-BEAM IND HOT IN RUN OR START HYDRO-BOOST PRESSURE WARNING SWITCH (NEAR MASTER CYLINDER) ILLUM LAMP ILLUM. LAMPS IN-LINE DIODE (BEHIND LEFT SIDE OF I/P, ABOVE FUSE BLOCK) IN-LINE DIODE (BEHIND LEFT SIDE OF I/P, ABOVE STEERING COLUMN) INSTRUMENT CLUSTER LEFT TURN IND LOW COOLANT IND LT BLU WIRE LT BLU/BLK WIRE LT GRN WIRE LT GRN/BLK WIRE MAL- FUNCTION IND OIL PRESS GAUGE PARK BRAKE WARNING SWITCH PNK PNK WIRE PNK WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (UNDER DRIVER'S SEAT) PPL RESISTOR RIGHT TURN IND SAFETY BELT IND SPEED- OMETER TAN WIRE TAN/WHT WIRE VEHICLE SPEED SENSOR (REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (BEHIND LEFT SIDE OF I/P) VOLT- METER W/ DRL W/ DRL PPL PPL W/O DRL WARNING SYSTEMS WHT WIRE YEL WIRE

1995 VFTC ACCY ALT FUSE AUDIO ALARM MODULE CONVENIENCE CENTER BLK WIRE BRAKE IND BRAKE PRESSURE WARNING SWITCH (NEAR MASTER CYLINDER) BRAKE WARNING ALARM BUZZER MODULE (BRAKE WARNING HARNESS) BRN WIRE BRN/WHT WIRE BULB TEST COOLANT TEMP GAUGE DAYTIME RUNNING LAMPS MODULE (TOP RIGHT SIDE OF SHIPPING HARNESS) DAYTIME RUNNING LAMPS RELAY DAYTIME RUNNING LIGHTS IND DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/YEL WIRE ELECTRONIC DELAY MODULE (BRAKE WARNING HARNESS) ENGINE CONTROLS SYSTEM ENGINE COOLANT TEMPERATURE SENDER (LEFT FRONT OF ENGINE) FLOW SWITCH (BRAKE BOOSTER) FUEL GAUGE FUEL PUMP OIL PRESSURE SWITCH, SENDER (TOP REAR OF ENGINE) FUEL PUMP, SENDER (IN FUEL TANK) FUSE BLOCK GAUGES FUSE GRY WIRE HEAD- LIGHTS SYSTEM HEADLIGHTS SYSTEM HI-BEAM IND HOT IN RUN OR START HOT IN RUN, BULB TEST OR START HYDRO-BOOST PRESSURE WARNING SWITCH (BRAKE WARNING HARNESS) I/P GROUND (AT LEFT SHIPPING PANEL) IGNITION SWITCH ILLUM. LAMPS INSTRUMENT CLUSTER LEFT TURN IND LOCK OFF LT BLU WIRE LT BLU/BLK WIRE LT GRN WIRE LT GRN/BLK WIRE MAL- FUNCTION IND NCA WIRE OIL PRESS GAUGE PARK BRAKE IND PARK BRAKE WARNING SWITCH (PARK BRAKE PEDAL BRACKET) PNK PPL WIRE PNK WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF I/P, BEHIND SHIPPING PANEL) PPL RESISTOR RIGHT TURN IND. SAFETY BELT IND. RUN WIRE SHUNT SPEED- OMETER TAN WIRE TAN/WHT WIRE VEHICLE SPEED SENSOR (REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (LEFT SIDE OF SHIPPING PANEL) VOLT- METER W/ DRL W/O DRL WHT WIRE YEL WIRE

1995 VFTC ACCY ACCY BULB TEST LOCK OFF AUDIO ALARM MODULE CONVENIENCE CENTER BATTERY BATTERY JUNCTION BLOCK BLK WIRE BLK/RED WIRE BLOWER SWITCH RIGHT POWER WINDOW SWITCH BRN WIRE BULB TEST CONVENIENCE CENTER DAYTIME RUNNING LAMPS RELAY DK BLU WIRE DK GRN WIRE DRL FUSE PWR ACC CIRCUIT BREAKER FRONT DOME LAMP RADIO FUEL PUMP OIL PRESSURE SWITCH TURN SIGNAL FLASHER BACKUP LAMP SWITCH FUEL PUMP RELAY POWERTRAIN CONTROL MODULE (PCM) FUEL PUMP STOP-HZ FUSE FUSE FUSE BLOCK FUSIBLE FUSIBLE LINK GENERATOR GRY WIRE HEADLIGHT SWITCH HEATER RADIO CONTROL LAMP HIGH BLOWER RELAY HORN RELAY HORN/DM TAIL LPS FUSE FUSE SHUNT IGNITION COIL IGNITION SWITCH INSTR LPS FUSE INSTRUMENT CLUSTER LEFT DOOR LOCK SWITCH DOOR LOCK RELAY LEFT POWER WINDOW SWITCH LIGHT SWITCH LINK LOCK OFF NCA WIRE ORG/ WIRE ORG/BLK WIRE PNK WIRE PPL PROVISIONS FOR REAR DOME LAMP PWR WDO CIRCUIT BREAKER HTR A/C FUSE RADIO WINDSHIELD WIPER/ WASHER SWITCH WINDSHIELD WIPER MOTOR MODULE RED WIRE RIGHT DOOR LOCK SWITCH RUN WIRE STARTER SOLENOID STOPLAMP SWITCH HAZARD FLASHER AUDIO ALARM MODULE TO ECM I, GAGES, TRANS FUSES AND TRANSMISSION RANGE INDICATOR LAMP TURN-B/U FUSE RADIO WIPER FUSE FUSE W/ A/C W/ A/C W/O A/C W/O A/C WHT WIRE YEL WIRE

85 30 PPL BLK WIRE BRAKE/ BRAKE/TRANSMISSION SHIFT INTERLOCK (BTSI) SOLENOID (ON STEERING COLUMN) BRN WIRE DIESEL DIESEL ONLY DK GRN/WHT WIRE ELECTRONIC BRAKE CONTROL MODULE (BELOW RADIATOR ON CROSSMEMBER) GASOLINE HOT IN RUN I-3 FUSE I/P FUSE BLOCK PARK/NEUTRAL POSITION AND BACKUP LAMPS SWITCH (LEFT OF TRANS) PPL TORQUE CONVERTER CLUTCH AND STOP LAMPS SWITCH (RIGHT SIDE OF STEERING COLUMN) TRANS- MISSION CONTROL MODULE (TCM) (LEFT INTERIOR FIREWALL) TURN SIGNAL FLASHER (ON FUSE BLOCK) TURN-B/U FUSE VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENG COMPT) IGN YEL WIRE

BLK WIRE GAUGES FUSE 8 GRY WIRE HORN/DM FUSE 3 HOT AT ALL TIMES HOT IN RUN AND START HOT W/ PARK OR HEADLAMPS SWITCH ON I/P FUSE BLOCK INSTR LPS FUSE 16 INSTRUMENT CLUSTER LAMP ON INPUT GROUND POWER (BATTERY) SEAT BELT INPUT ORG/ WIRE PNK POWER (IGNITION) WIRE PNK WIRE SEAT BELT LAMP OUTPUT SEAT BELTS ALARM MODULE (AT THE BOTTOM OF THE I/P FUSE BLOCK) YEL WIRE