GMC Pickup C3500 (1985-2000) red Wiring diagrams

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID A/T ISS SENS HI IN A/T ISS SENS IN A/T ISS SENS LO IN A/T ISS SENSOR OUT ACCELERATOR PEDAL POSITION MODULE (PART OF ACCELERATOR PEDAL) APP 1 SIGNAL IN APP 2 SIGNAL IN APP 3 SIGNAL IN AUTOMATIC TRANSMISSION AUTOMATIC TRANSMISSION INPUT SHAFT SPEED SENSOR (LEFT FRONT OF TRANSMISSION) BATTERY IN BLK WIRE BLK/WHT WIRE BLU/WHT WIRE BRAKE FUSE 18 BRAKE SWITCH ASSEMBLY (ON BRAKE PEDAL BRACKET) BRAKE SWITCH IN BRN WIRE BRN/WHT WIRE CLASS II DATA DK BLU WIRE DK GRN WIRE ECM-B FUSE ECT SENSOR IN ENGINE COOLANT TEMP SENSOR (NEAR THERMOSTAT HOUSING) FRONT WHEEL LOCK FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GAUGES FUSE 4 GROUND GRY WIRE GRY/BLK WIRE HI PPL HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START HOT IN RUN OR START UNDERHOOD FUSE/RELAY CENTER ECM 1 FUSE HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LT BLU WIRE 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 PNK WIRE PNK WIRE POWER POWERTRAIN CONTROL MODULE (RIGHT SIDE OF DASH NEAR BLOWER MOTOR) PPL PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) PPL/WHT WIRE PRESS CTRL SOLENOID LO RED WIRE RED/BLK WIRE SENSOR GROUND STOP/HAZ FUSE 1 STOPLAMP SWITCH IN TAN WIRE TAN/WHT WIRE TCC PWM SOL TCC PWM SOLENOID TFT SENSOR IN TRANS FLUID TEMP SENSOR TRANS FUSE 20 TRANS RANGE "A" TRANS RANGE "B" TRANS RANGE "C" TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANS RANGE SWITCHES TRANSFER CASE CIRCUIT PNK WIRE TRANSFER CASE, AXLE SWITCHES TURN/ HAZARD SWITCH, CHIME MODULE VEHICLE SPEED SENSOR VEHICLE SPEED SENSOR (VSS) ADAPTOR VEHICLE SPEED SENSOR BUFFER (RIGHT SIDE OF DASH) VSS HI IN VSS IN VSS LO IN VSS OUT WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 2-3 SHIFT SOL 3-2 SHIFT SOL TRANS FLUID TEMP (TFT) SENSOR 999 998 961 452 389 995 PPL ACCELERATOR PEDAL POSITION (APP) MODULE (TOP OF ACCEL- ERATOR BRACKET) APP #3 APP #3 SENSOR SIG APP 1 APP 2 BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRN WIRE BRN/WHT WIRE DATA LINK CONNECTOR (BELOW LEFT SIDE OF DASH) DK BLU WIRE DK GRN WIRE ECM I FUSE ECM-B FUSE ENGINE COOLANT TEMPERATURE (ECT) SENSOR (LEFT LOWER FRONT OF ENGINE BLOCK) GAUGES FUSE GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK IGNITION FEED 3-2 CONTROL SOL DIAGNOSTIC REQUEST WIRE PNK WIRE POWERTRAIN CONTROL MODULE (UNDER RIGHT SIDE OF DASH) PPL PPL TCC/BRAKE SW PPL/WHT WIRE PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SERVICE ENGINE SOON SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) STOP/HAZ FUSE 1 TAN WIRE TAN/BLK WIRE TCC PWM SOL TCC SOL TCC/STOP LAMP SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) TRANS FUSE 20 TRANSFER CASE SWITCH TRANSMISSION UNDERHOOD FUSE/RELAY CENTER VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF DASH) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 2-3 SHIFT SOL 3-2 SHIFT SOL ACCELERATOR PEDAL POSITION (APP) MODULE (TOP OF ACCEL- ERATOR BRACKET) APP #3 APP #3 SENSOR SIG APP 1 APP 2 BLK WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE DATA LINK CONNECTOR (BELOW LEFT SIDE OF DASH) DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE ECM I FUSE ECM-B FUSE ENGINE COOLANT TEMPERATURE (ECT) SENSOR (LEFT LOWER FRONT OF ENGINE BLOCK) GAUGES FUSE GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK IGNITION FEED DIAGNOSTIC REQUEST WIRE PNK WIRE POWERTRAIN CONTROL MODULE (UNDER RIGHT SIDE OF DASH) PPL PPL TCC/BRAKE SW PPL/WHT WIRE PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SERVICE ENGINE SOON SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) STOP/HAZ FUSE 1 TAN WIRE TCC/STOP LAMP SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) TRANS FLUID TEMP (TFT) SENSOR TRANS FUSE 20 TRANS INPUT SPD SIG LO TRANSFER CASE SWITCH TRANSMISSION TRANSMISSION INPUT SPEED SENSOR (FRONT OF TRANSMISSION) UNDERHOOD FUSE/RELAY CENTER VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF DASH) WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

ALL OTHERS BLK WIRE BRN WIRE CHARGE INDICATOR FUSIBLE LINK (10 GA-RUST) GAUGES FUSE 4 GENERATOR GENERATOR (W/ DUAL GENERATORS) HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) INSTRUMENT CLUSTER LEFT BATTERY (DIESEL) MEGA FUSE BLOCK (RIGHT FRONT OF ENGINE COMPT, NEAR BATTERY) PNK 22 WIRE PNK WIRE POWER DISTRIBUTION SYSTEM RED WIRE RIGHT BATTERY UPLEVEL/ ENHANCED

AUDIO ALARM MODULE AUXILIARY HEATER/ A/C CONTROL REAR AUXILIARY REAR HEATER/ WIPER/ A/C CONTROL WASHER FRONT SWITCH CARGO LAMP SWITCH CONVENIENCE CENTER CTSY FUSE 3 DAYTIME RUNNING LAMPS RELAY DIODE DK GRN WIRE DRL/FOG FUSE 15 FOG FOG LAMP LAMP RELAY RELAY FOG LAMP SWITCH FROM MAXI FUSE 8 FRONT DOME/ READING LAMPS GLOVE BOX LAMP) GRY WIRE HEADLAMP AND PANEL DIMMER SWITCH I/P FUSE BLOCK ILLUM FUSE 14 INSTRUMENT CLUSTER LEFT FRONT DOOR COURTESY LAMP LEFT I/P SPARE COURTESY POWER LAMP SOURCE LEFT REAR DOOR COURTESY LAMP LEFT VANITY MIRROR ORG/ WIRE PARK LAMPS PICKUP ONLY PICKUP SUBURBAN, UTILITY PK LPS FUSE 9 RADIO HEATER/ CARGO LAMP A/C CONTROL SWITCH LAMP REAR DOME READING LAMPS REAR LIFTGATE RELEASE SWITCH RED WIRE REMOTE OUTSIDE MIRROR SWITCH RIGHT FRONT DOOR COURTESY LAMP RIGHT I/P COURTESY LAMP RIGHT REAR DOOR COURTESY LAMP RIGHT VANITY MIRROR SUBURBAN ONLY SUBURBAN, UTILITY ONLY TWO WHEEL DRIVE INDICATOR

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 RR+ RR- ANTENNA BARE BLK WIRE BRN WIRE CIG LTR FUSE 13 DIESEL GAS DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE GRY WIRE HOT AT ALL TIMES HOT IN ACC OR RUN I/P FUSE BLOCK LEFT FRONT SPEAKER LEFT FRONT TWEETER LEFT REAR DOOR SPEAKER LEFT REAR SPEAKER LR DR - RLY SIG GROUND LR DR + LR+ LR- RR DR + LT BLU WIRE LT GRN WIRE NCA WIRE ORG/ WIRE ORG/BLK WIRE PNK WIRE POWER AMPLIFIER (UNDER LEFT SIDE OF DASH) POWER AMPLIFIER RELAY (UNDER LEFT SIDE OF DASH) PPL/WHT WIRE RADIO RADIO BATT FUSE 19 RADIO FUSE 17 RED WIRE REMOTE AUDIO PLAYER RIGHT FRONT SPEAKER RIGHT FRONT TWEETER RIGHT REAR DOOR SPEAKER RIGHT REAR SPEAKER RR DR - SERIAL DATA VSS SIGNAL RR - RR + LR _ LR + TAN WIRE VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPARTMENT) VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF DASH) VSS SIGNAL WHT WIRE YEL WIRE

A/T ACCY BLK WIRE BULB TEST CRANK FUSE 8 DIESEL EXCEPT DIESEL (BASE) EXCEPT DIESEL (UPLEVEL) HOLD- IN COIL I/P FUSE BLOCK (LEFT SIDE OF DASH, IGN A FUSE 6 IGNITION SWITCH LEFT BATTERY (DIESEL) LOCK OFF MEGA FUSE BLOCK (RIGHT FRONT OF ENGINE COMPT, NEAR BATTERY) NCA WIRE POWER DISTRIBUTION SYSTEM PPL PPL (RIGHT FRONT WHEELHOUSE) CLUTCH PEDAL POSITION SWITCH (TOP OF CLUTCH PEDAL) PPL A/T M/T PPL PPL PULL- IN COIL RED WIRE REMOTE BATTERY STUD RIGHT BATTERY RUN WIRE STARTER MOTOR STARTER RELAY STARTER SOLENOID TRANSMISSION RANGE SWITCH (LEFT SIDE OF TRANSMISSION) WHT WIRE YEL WIRE

5 CM FROM TRANSFER CASE BREAK-OUT) BLK WIRE BLK/WHT WIRE BRN WIRE CONVENIENCE CENTER DIESEL FROM ENGINE HARN BREAK-OUT) FRONT AXLE ACTUATOR FRONT AXLE SWITCH FUSE 24 GASOLINE GRY WIRE GRY/BLK WIRE HOT IN PARK OR HEAD HOT IN RUN I/P FUSE BLOCK ILLUM FUSE 14 INDICATOR LT BLU WIRE POWERTRAIN CONTROL MODULE (REARWARD OF LEFT SHOCK TOWER) RED WIRE TRANSFER CASE MODE SELECTOR ILLUMINATION LAMP TRANSFER CASE RELAY TRANSFER CASE SWITCH (TOP LEFT OF TRANSFER CASE) TRANSFER CASE SYNCHRONIZER

5 CM FROM TRANSFER CASE BREAK-OUT) BLK WIRE BLK/WHT WIRE BRN WIRE CONVENIENCE CENTER DIESEL FROM ENGINE HARN BREAK-OUT) FRONT AXLE ACTUATOR FRONT AXLE SWITCH FUSE 24 GASOLINE GRY WIRE GRY/BLK WIRE HOT IN PARK OR HEAD HOT IN RUN I/P FUSE BLOCK ILLUM FUSE 14 INDICATOR LT BLU WIRE POWERTRAIN CONTROL MODULE (REARWARD OF LEFT SHOCK TOWER) RED WIRE TRANSFER CASE MODE SELECTOR ILLUMINATION LAMP TRANSFER CASE RELAY TRANSFER CASE SWITCH (TOP LEFT OF TRANSFER CASE) TRANSFER CASE SYNCHRONIZER

5 CM FROM TRANSFER CASE BREAK-OUT) BLK WIRE BLK/WHT WIRE BRN WIRE CONVENIENCE CENTER DIESEL FROM ENGINE HARN BREAK-OUT) FRONT AXLE ACTUATOR FRONT AXLE SWITCH FUSE 24 GASOLINE GRY WIRE GRY/BLK WIRE HOT IN PARK OR HEAD HOT IN RUN I/P FUSE BLOCK ILLUM FUSE 14 INDICATOR LT BLU WIRE POWERTRAIN CONTROL MODULE (REARWARD OF LEFT SHOCK TOWER) RED WIRE TRANSFER CASE MODE SELECTOR ILLUMINATION LAMP TRANSFER CASE RELAY TRANSFER CASE SWITCH (TOP LEFT OF TRANSFER CASE) TRANSFER CASE SYNCHRONIZER