GMC Forward Control P3500 (1985-1999) red 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

BAT BAT (BASE) GENERATOR BATTERY BLK WIRE FUSIBLE LINK FUSIBLE LINK (10 GA-RUST) GASOLINE DIESEL GAUGES FUSE HOT IN RUN AND START I/P FUSE BLOCK INSTRUMENT CLUSTER TACH (DIESEL) PNK (COMMERCIAL) (MOTOR HOME) PNK WIRE PNK WIRE POWER DISTRIBUTION SYSTEM RED (OR GRY) WIRE RED WIRE SECONDARY BATTERY (DIESEL) STARTER SOLENOID WHT WIRE

ACCY AUTO APPLY FUSE 19 BATTERY JUNCTION BLOCK BLK WIRE BLK/WHT WIRE BRAKE PRESSURE DIFFERENTIAL SWITCH (INTERNAL TO ELECTRONIC BRAKE CONROL MODULE) DAYTIME RUNNING LAMPS MODULE DIODE DIODE NETWORK (DASH HARN, DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE (EBCM) (BELOW RADIATOR, ON LOWER CROSSMEMBER) FROM FUSE BLOCK) FUSE BLOCK FUSIBLE LINK GAS DIESEL HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) IGNITION SWITCH LOCK OFF LT BLU WIRE LT GRN WIRE NCA WIRE ORG/ WIRE PARK BRAKE ACTUATOR POSITION SWITCH PARK BRAKE ALARM PARK BRAKE ALARM RELAY (ON I/P HARNESS) (BODY BUILDER INSTALLED) PARK BRAKE PULL BUTTON RELAY (ON I/P HARNESS) (BODY BUILDER INSTALLED) PARK/NEUTRAL POSITION SWITCH RELAY (ON RIGHT SIDE OF DRIVER'S ISLAND) PNK PNK WIRE PNK WIRE PNK/BLK WIRE PPL RED WIRE RUN WIRE SHIFT INTERLOCK SYSTEM TAN/WHT WIRE W/ DRL W/ DRL W/O DRL PARK BRAKE INDICATOR SWITCH (BODY BUILDER INSTALLED) W/O DRL WHT WIRE YEL WIRE YEL/BLK WIRE

1996 VFTC A/C COMPRESSOR CLUTCH RELAY AUXILIARY ENGINE COOLANT FAN RELAY (DIESEL ONLY) BATT BUS BATTERY BATTERY JUNCTION BLOCK (LEFT SIDE OF ENGINE BULKHEAD, ABOVE RELAY BRACKET) BLK WIRE DATA LINK CONNECTOR (DLC) DIESEL DOME LAMP (PROVISIONS FOR) ECM BAT FUSE ENG-BAT FUSE FUEL PUMP RELAY FUEL PUMP SWITCH, ENGINE OIL PRESSURE GAUGE SENSOR FUSIBLE LINK (10 GA-RUST) FUSIBLE LINK (16 GA- FUSIBLE LINK 12 GA. BLUE FUSIBLE LINK 18 GA. BLUE FUSIBLE LINK 18 GA. RUST GAS GENERATOR (RIGHT FRONT OF ENGINE) GLOW PLUG CONTROL SWITCH (DIESEL ONLY) GRY WIRE HAZARD WARNING LAMPS FLASHER HEADLAMPS SWITCH HORN RELAY HORN/ DM FUSE TAIL LPS FUSE I/P FUSE BLOCK (DASH PANEL PROVIDED BY BODY BUILDER) (BODY BUILDER INSTALLED) IGNITION SWITCH ORG/ WIRE PWR BUS PWR FUSE RED WIRE REMOTE BATTERY ACCESS TERMINAL BLOCK (REAR OF RIGHT RADIATOR CORE SUPPORT PANEL) SEAT BELT ALARM SECONDARY BATTERY (DIESEL ONLY) STARTER RELAY STARTER SOLENOID (AT STARTER, LOWER RIGHT SIDE OF ENGINE) STOP/ HAZ FUSE STUD TO HEADLAMPS SWITCH (CAVITY E) TORQUE CONVERTER CLUTCH, STOPLAMPS SWITCH TRANSMISSION CONTROL MODULE (A/T ONLY) VEHICLE CONTROL MODULE (VCM) W/DELUXE SCHOOL BUS

1996 VFTC ACC BUS AUTOMATIC TRANSMISSION AUTOMATIC TRANSMISSION (A/T) BRN WIRE CLUTCH PEDAL POSITION (CPP) SWITCH CRK (START) LOCK ON (RUN) OFF CRK (START) ON (RUN) LOCK OFF CRK (START) ON (RUN) OFF DIESEL DK BLU WIRE ENG 1 FUSE EVAPORATIVE EMISSIONS (EVAP) CANISTER PURGE SOLENOID VALVE FROM FUSIBLE LINK FUEL HEATER FUSE OUTPUT- ACCESSORY TYPE 3 FUSE GAS GLOW PLUG CONTROL SWITCH HEATED OXYGEN SENSOR HEATED OXYGEN SENSOR CAMSHAFT POSITION (CMP) SENSOR I/P FUSE BLOCK (DASH PANEL PROVIDED BY BODY BUILDER) (BODY BUILDER INSTALLED) IGNITION SWITCH LEFT POST CONVERTER (5.7L VIN R LEFT PRE- CONVERTER LINEAR EXHAUST GAS RECIRC- ULATION (EGR) SOLENOID VALVE LOCK MANUAL TRANSMISSION MASS AIR FLOW (MAF SENSOR) NCA WIRE ORG/ WIRE PARK/NEUTRAL POSITION (PNP), BACKUP LAMPS SWITCH PNK PNK WIRE PNK WIRE POST CONVERTER (4.3L VIN W PROVISIONS FOR WIPER/ WASHER MOTOR RADIO FUSE RED WIRE RIGHT POST CONVERTER (5.7L VIN R RIGHT PRE- CONVERTER TO I/P FUSE BLOCK: (AUX, I-3, TURN B/U,, HTR FUSES) TRANS FUSE VEHICLE CONTROL MODULE (VCM) WATER- IN-FUEL SENSOR AUXILIARY ENGINE COOLANT FAN RELAY WHT WIRE WINDSHIELD WIPER/ WASHER SWITCH WIPER FUSE YEL WIRE

1996 VFTC 6.5L VIN F 6.5L VIN F 7.4L VIN J 7.4L VIN J (L29), 6.5L VIN F (L65) ENGINES ONLY 7.4L VIN N A/C COMPRESSOR CONTROL RELAY BATTERY BATTERY JUNCTION BLOCK (ON FORWARD LEFT SIDE OF THE BULKHEAD) BLANK FUSE BLK WIRE BUSS BAR DATA LINK CONNECTOR (DLC) DIESEL ONLY DOME LAMP ENG-BAT FUSE FAN CONTROL RELAY FUEL PUMP RELAY FUSIBLE LINK (10 GA-RUST) FUSIBLE LINK (14 GA- FUSIBLE LINK (16 GA- FUSIBLE LINK 12 GA. BLUE FUSIBLE LINK 18 GA. BLUE GENERATOR (ON RIGHT FRONT OF ENGINE) GLOW PLUG CONTROL RELAY HAZARD LAMPS FLASHER HEADLAMPS SWITCH HORN RELAY HORN- DM FUSE I/P FUSE BLOCK (MOUNTED ON THE I/P) IGNITION SWITCH ONLY ORG/ WIRE POWERTRAIN CONTROL MODULE (PCM) POWERTRAIN CONTROL MODULE (PCM) VEHICLE CONTROL MODULE (VCM) PWR CIRCUIT BREAKER RED WIRE SEAT BELTS/ LAMPS ALARM MODULE SECONDARY BATTERY (DIESEL ONLY) STARTER MOTOR (ON RIGHT REAR SIDE OF ENGINE) STARTER RELAY STOP- HAZ FUSE ECM- BAT FUSE TAIL LAMPS FUSE TO HEADLAMPS SWITCH (CAVITY E) TORQUE CONVERTER CLUTCH (TCC), STOPLAMPS SWITCH

14 GA (BLK) WIRE 1996 VFTC 7.4L VIN J (L29) ENGINE, 7.4L VIN N (L19) ENGINE 7.4L VIN J, 6.5L VIN F ENGINES AUTOMATIC TRANSMISSION BRN WIRE CAMSHAFT POSITION SENSOR (7.4L VIN J DK BLU WIRE ECM-1 FUSE,, GAUGES FUSE ENG-1 FUSE TRANS FUSE ENGINE EVAPORATIVE EMISSIONS CANISTER PURGE SOLENOID (7.4L VIN J FAN CONTROL RELAY FROM FUSIBLE LINK FUEL HEATER (6.5L VIN F ENGINE) FUSE OUTPUT- ACCESSORY TYPE 3 FUSE GLOW PLUG CONTROL RELAY (6.5L VIN F ENGINE) HEATED OXYGEN SENSOR NO.1 HEATED OXYGEN SENSOR NO.2 HEATED OXYGEN SENSOR NO.3 HEATED OXYGEN SENSOR NO.4 I/P AUXILIARY FUSE BLOCK (MOUNTED ON I/P FUSE BLOCK) CRANK FUSE I/P FUSE BLOCK (MOUNTED ON THE I/P) IGNITION COIL (7.4L VIN N ENGINE) IGNITION SWITCH LOCK OFF MASS AIR FLOW SENSOR (7.4L VIN J ENGINE) NCA WIRE ORG/ WIRE PNK PNK WIRE PNK WIRE PPL PROVISIONS FOR WIPER/WASHER MOTOR RADIO FUSE RED WIRE RUN WIRE STARTER SOLENOID (7.4L VIN N ENGINE) VEHICLE CONTROL MODULE LINEAR EGR SOLENOID VALVE WATER IN-FUEL INDICATOR SENSOR (6.5L VIN F ENGINE) WHT WIRE WIPER FUSE YEL WIRE

A/T ACCY BATTERY BATTERY JUNCTION BLOCK BLK WIRE CLUTCH PEDAL POSITION SWITCH (TOP OF CLUTCH PEDAL SUPPORT) DIESEL ONLY DK BLU WIRE DK BLU/WHT WIRE ENGINE CONTROLS SYSTEM (COMMERCIAL DIESEL ONLY) FUSIBLE LINK FUSIBLE LINK (10 GA-RUST) IGNITION SWITCH IN LINE CRANK FUSE 18 (COMMERCIAL) OR I/P FUSE BLOCK, CRANK FUSE 18 (MOTOR HOME) LOCK M/T OFF PARK/NEUTRAL POSITION AND BACKUP LAMPS SWITCH (LEFT SIDE OF TRANSMISSION) PPL PPL M/T PULL- IN COIL HOLD- IN COIL RED WIRE RUN WIRE SECONDARY BATTERY (DIESEL) STARTER MOTOR STARTER SOLENOID WHT WIRE YEL WIRE

BATTERY JUNCTION BLOCK (ON FORWARD LEFT SIDE OF BULKHEAD) BLK WIRE BLK/RED WIRE BRN WIRE BRN/WHT WIRE BYPASS DIST. REF HI DIST. REF LO DISTRIBUTOR DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM 1 FUSE FUEL GAUGE FUEL PUMP PRIME CONNECTOR FUEL PUMP RELAY (AT RELAY CENTER RIGHT SIDE OF MAIN SUPPORT AT DRIVER'S ISLAND) FUEL PUMP, SENDER (ON TOP OF FUEL TANK) FUSIBLE LINK (16 GA- GAUGES FUSE GRY WIRE HIGH VOLTAGE IGNITION COIL WIRE HOT AT ALL TIMES HOT IN RUN, START (CRANK) I/P FUSE BLOCK (MOUNTED ON THE I/P) IGNITION COIL (ON BRACKET AT REAR OF INTAKE PLENUM) IGNITION MODULE IGNITION SWITCH INSTRUMENT CLUSTER LOCK OFF OIL PRESS GAUGE ORG/ WIRE PICKUP COIL PNK 9 10 11 12 13 14 15 16 WIRE PNK PNK 1 2 3 4 5 WIRE PNK WIRE PPL PPL/WHT WIRE RED WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR SPEED METER TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE THROTTLE BODY FUEL INJECTOR NO.1 (ON TOP OF INTAKE MANIFOLD) THROTTLE BODY FUEL INJECTOR NO.2 (ON TOP OF INTAKE MANIFOLD) WHT WIRE