GMC Pickup C3500 (1985-2000) red Wiring diagrams

AUXILIARY LEAD (TAPED NEAR FUSE BLOCK) BLK WIRE BLU WIRE BRN WIRE CARGO CHMSL CARGO LAMP SWITCH CARGO/ CHMSL LAMPS CLEARANCE LAMPS CIRCUIT (W/DUAL REAR WHEELS) CONVENIENCE CENTER (BEHIND INTERIOR LEFT SIDE LIGHTS SYSTEM OF I/P) CONVENIENCE CENTER (BEHIND LEFT SIDE OF I/P) CRUISE CONTROL SYSTEM CTSY LPS DK BLU WIRE DK DK DK GRN WIRE FUSE 1 FUSE 16 FUSE 3 FUSE 9 FUSE BLOCK (LOWER LEFT SIDE OF I/P) GRN WIRE HAZARD HAZARD FLASHER HEADLIGHT/ PANEL DIMMER SWITCH HOT AT ALL TIMES HOT AT ALL TIMES U/H FUSE/ RELAY CENTER (LEFT REAR ENGINE COMPT) HOT IN RUN, BULB TEST OR START IDENTIFICATION LAMPS INSTRUMENT CLUSTER LEFT BACKUP LIGHT LEFT CLEAR- ANCE LAMP LEFT FRONT MARKER LIGHT LEFT FRONT PARK/ TURN LIGHTS LEFT TAIL/ STOP/ TURN LIGHT LEFT TURN IND LEFT TURN, HAZARD LH RH LICENSE LICENSE LIGHTS LIGHT LT BLU WIRE LT DK LT GRN WIRE LT LT M/T A/T MAXI FUSE 2 NORMAL ORG/ WIRE PARADE MODE SW PARK LPS PARK RHEO- STAT OFF PLATFORM HITCH GROUND PNK M/T A/T WIRE PNK WIRE PPL RED WIRE RIGHT BACKUP LIGHT RIGHT CLEAR- DK ANCE LAMP RIGHT FRONT MARKER LIGHT RIGHT FRONT PARK/ TURN LIGHTS RIGHT TAIL/ STOP/ TURN LIGHT RIGHT TURN IND RIGHT TURN, HAZARD STOP HAZ STOP LAMP RELAY STOP LAMP/ TCC SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) TURN B/U TURN FLASHER TURN/ HAZARD SWITCH U/H FUSE/ RELAY CENTER (LEFT REAR ENGINE COMPT) W/ STEP W/O STEP BUMPER BUMPER W/OPTIONAL TRAILER TOW PACKAGE WHT WIRE WIRE LEADS ARE SPLICED TO TRAILER WIRING, OR CONNECTED TO TRAILER WIRE PLUG YEL WIRE

& CRUISE FUSES A/T M/T AUX FAN MINI FUSE AUXILIARY COOLING FAN RELAY BLK WIRE BLK/RED WIRE BRAKE LAMP RELAY BRAKE PRESSURE MODULATOR VALVE BRN WIRE CRANK FUSE 8 DIAGNOSTIC ENERGY RESERVE MODULE FUEL PUMP RELAY FUSIBLE HEATER-A/C CONTROL I/P FUSE BLOCK IGNITION SWITCH INSTRUMENT CLUSTER LEFT RIGHT BATTERY BATTERY LINK LOCK LOCK OFF MAXI FUSE MAXI FUSE 2 MAXI FUSE 4 MAXI FUSE 5 MAXI FUSE 6 MAXI FUSE 7 MAXI FUSE 8 NCA WIRE OFF ORG/ WIRE PNK WIRE PPL RED WIRE REMOTE BATTERY STUD RR-DEFOG MINI FUSE RUN WIRE STARTER GENERATOR MOTOR SOLENOID TO BLOWER RELAYS TO CTSY, PK LPS, DRL/FOG FUSES, HEAD- LAMP SWITCH TO ECM-B, HORN, A/C COMP FUSES TO GAUGES, AIR BAG FUSES TO HTR-A/C, TO IGN-E, ECM-I, ENG-1 FUSES TO RADIO/ BATT, CIG LTR, AUX PWR FUSES, PWR ACCY BREAKER TO WIPER, RADIO, REAR WIPER FUSES TRANS FUSE 20 TRANS- MISSION TRANSMISSION CLUTCH RANGE SWITCH SWITCH UNDERHOOD FUSE-RELAY CENTER WHT WIRE YEL WIRE

A/C COMP MINI FUSE A/C LOW PRESSURE CUTOUT SWITCH AUXILIARY COOLING FAN RELAY BRN WIRE CONVENIENCE CENTER ECM-B MINI FUSE ECM-I MINI FUSE ELECTRONIC INJECTION PUMP ENG-I MINI FUSE FROM AUX FAN FUSE FROM IGNITION SWITCH FROM MAXI FUSE 6 FUEL PUMP OIL PRESSURE SWITCH/ SENDER FUEL PUMP RELAY FUEL SOL MINI FUSE GLOW PLUG RELAY HIGH BLOWER RELAY HORN MINI FUSE HORN RELAY I/P FUSE BLOCK IGN E MINI FUSE LOW BLOWER RELAY MAXI FUSE 3 MEDIUM BLOWER RELAY ORG/ WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) RADIO RADIO FUSE 17 REAR WIPER FUSE 23 REAR WIPER/ WASHER SWITCH RED WIRE SUBURBAN ONLY SUBURBAN, UTILITY ONLY TO POWER WINDOW CIRCUIT BREAKER UNDER HOOD FUSE-RELAY CENTER UNDERHOOD FUSE-RELAY CENTER UNDERHOOD REEL LAMP WATER EGR IN FUEL SOLENOID SENSOR VALVE WHT WIRE WIPER FUSE 11 WIPER MOTOR MODULE WIPER/ WASHER SWITCH YEL WIRE

ALL EXCEPT PICKUP, 2 DOOR UTILITY W/O KEYLESS ENTRY AMPLIFIER RELAY AUDIO ALARM MODULE CONVENIENCE CENTER AUX PWR FUSE 7 AUXILIARY POWER FEED AUXILIARY POWER SUPPLY SOCKET BLK WIRE BUCKETS OR SPLIT BENCH ONLY CIG LTR FUSE 13 CIGARETTE LIGHTER CONVENIENCE CENTER DOOR RIGHT LOCK FRONT RELAY DOOR LOCK SWITCH FROM MAXI FUSE 7 HAZARD FLASHER (CONVENIENCE CENTER) I/P FUSE BLOCK LEFT LEFT FRONT FRONT POWER DOOR SEAT LOCK SWITCH LEFT REAR FRONT LIFTGATE DOOR RELEASE LOCK SWITCH SWITCH LEFT RIGHT FRONT FRONT POWER POWER LUMBAR LUMBAR SWITCH SWITCH ORG/ WIRE PICKUP/2 DOOR UTILITY W/O KEYLESS ENTRY ALL OTHER POWER ACCY CIRCUIT BREAKER RADIO RADIO BATT FUSE 19 RED WIRE REMOTE KEYLESS ENTRY MODULE RIGHT FRONT DOOR LOCK SWITCH STOP/ HAZARD FUSE 1 SUBURBAN, UTILITY ONLY TCC/ STOPLAMP SWITCH

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

& CRUISE FUSES A/T M/T AUX FAN MINI FUSE AUXILIARY COOLING FAN RELAY BATTERY BLK WIRE BLK/RED (OR BLK) WIRE BRAKE LAMP RELAY BRAKE PRESSURE MODULATOR VALVE BRN WIRE CRANK FUSE 8 DIAGNOSTIC ENERGY RESERVE MODULE EXCEPT 4.3L FUSIBLE HEATER-A/C CONTROL I/P FUSE BLOCK IGNITION SWITCH INSTRUMENT CLUSTER LINK LOCK LOCK OFF M/T ONLY MAXI FUSE MAXI FUSE 2 MAXI FUSE 4 MAXI FUSE 5 MAXI FUSE 6 MAXI FUSE 7 MAXI FUSE 8 NCA WIRE OFF ORG/ WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) PPL RED WIRE REMOTE BATTERY STUD RR-DEFOG MINI FUSE RUN WIRE STARTER GENERATOR MOTOR SOLENOID TO BLOWER RELAYS TO CTSY, PK LPS, DRL/FOG FUSES, HEAD- LAMP SWITCH TO ECM-B, HORN, A/C COMP FUSES TO GAUGES, AIR BAG FUSES TO HTR-A/C, TO IGN-E, ECM-I, ENG-1 FUSES TO RADIO/ BATT, CIG LTR, AUX PWR FUSES, PWR ACCY BREAKER TO WIPER, RADIO, REAR WIPER FUSES TRANS FUSE 20 TRANS- MISSION TRANSMISSION CLUTCH RANGE SWITCH SWITCH UNDERHOOD FUSE-RELAY CENTER WHT WIRE YEL WIRE

4.3L, 5.0L, 5.7L ONLY 5.7L W/ H/D A/T A/C COMP MINI FUSE A/C LOW PRESSURE CUTOUT SWITCH AUXILIARY FUEL COOLING CYCLE FAN CONTROL RELAY MODULE BRN WIRE CONVENIENCE CENTER ECM-B MINI FUSE ECM-I MINI FUSE EGR ELECTRONIC VACUUM REGULATOR SOLENOID ELECTRONIC HEATED SPARK OXYGEN CONTROL SENSOR MODULE ENG-I MINI FUSE EXCEPT 4.3L 5.7L H/D W/ M/T FROM AUX FAN FUSE FROM IGNITION SWITCH FROM MAXI FUSE 6 FUEL INJECTOR 1 FUEL INJECTOR 2 FUEL PUMP OIL PRESSURE SWITCH/ SENDER FUEL PUMP RELAY HIGH BLOWER RELAY HORN MINI FUSE HORN RELAY I/P FUSE BLOCK IGN E MINI FUSE LOW BLOWER RELAY M/T ONLY MAXI FUSE 3 MEDIUM BLOWER RELAY ORG/ WIRE PNK WIRE POWERTRAIN CONTROL MODULE POWERTRAIN CONTROL MODULE (PCM) RADIO RADIO FUSE 17 REAR WIPER FUSE 23 REAR WIPER/ WASHER SWITCH RED WIRE SUBURBAN ONLY SUBURBAN, UTILITY ONLY TO POWER WINDOW CIRCUIT BREAKER UNDER HOOD FUSE-RELAY CENTER UNDERHOOD FUSE-RELAY CENTER UNDERHOOD REEL LAMP WHT WIRE WIPER FUSE 11 WIPER MOTOR MODULE WIPER/ WASHER SWITCH YEL WIRE

ALL EXCEPT PICKUP, 2 DOOR UTILITY W/O KEYLESS ENTRY AMPLIFIER RELAY AUDIO ALARM MODULE CONVENIENCE CENTER AUX PWR FUSE 7 AUXILIARY POWER FEED AUXILIARY POWER SUPPLY SOCKET BLK WIRE BUCKETS OR SPLIT BENCH ONLY CIG LTR FUSE 13 CIGARETTE LIGHTER CONVENIENCE CENTER DOOR RIGHT LOCK FRONT RELAY DOOR LOCK SWITCH FROM MAXI FUSE 7 HAZARD FLASHER (CONVENIENCE CENTER) I/P FUSE BLOCK LEFT LEFT FRONT FRONT POWER DOOR SEAT LOCK SWITCH LEFT REAR FRONT LIFTGATE DOOR RELEASE LOCK SWITCH SWITCH LEFT RIGHT FRONT FRONT POWER POWER LUMBAR LUMBAR SWITCH SWITCH ORG/ WIRE PICKUP ONLY PICKUP/2 DOOR UTILITY W/O KEYLESS ENTRY ALL OTHER POWER ACCY CIRCUIT BREAKER RADIO RADIO BATT FUSE 19 RED WIRE REMOTE KEYLESS ENTRY MODULE RIGHT FRONT DOOR LOCK SWITCH STOP/ HAZARD FUSE 1 SUBURBAN, UTILITY ONLY TCC/ STOPLAMP SWITCH

1222 1224 1225 1226 PNK WIRE 2-3 SHIFT SOL CTRL FUEL INJ CTRL EGR SOL CTRL ENG SHUT-OFF CTRL 4 WHEEL DRIVE LOW SWITCH 983 474 PPL 999 998 961 452 PPL ACCELERATOR PEDAL POSITION (APP) MODULE (TOP OF ACCELERATOR BRACKET) ANTI-LOCK BRAKES SYSTEM APP 1 SENSOR ENGINE COOLANT TEMPERATURE (ECT) SENSOR (RIGHT SIDE OF ENGINE) APP 2 SENSOR APP 3 SENSOR B/H BATTERY FEED FWD LOW SW BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BLU/WHT WIRE BRN WIRE BRN/WHT WIRE CRANK FUSE TRANS FUSE CRUISE CONTROL SYSTEM CRUISE ON/OFF SIG DATA LINK CONNECTOR (UNDER LEFT SIDE OF I/P) DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM-B FUSE ELECTRONIC 4-SPEED AUTOMATIC OVERDRIVE TRANSMISSION ENGINE SHUT- OFF SOLENOID (TOP FRONT OF ENGINE) FUEL INJ CTRL FUEL SOL FUSE FUEL SOLENOID (TOP FRONT OF ENGINE) FUEL SOLENOID DRIVER (TOP FRONT OF ENGINE) FUSE FUSE BLOCK GRY WIRE GRY/BLK WIRE GRY/RED WIRE HOT AT ALL TIMES HOT IN CRANK HOT IN RUN HOT IN START OR RUN LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE OPTICAL SENSOR AND FUEL TEMPER- ATURE SENSOR (TOP FRONT OF ENGINE) ORG/ WIRE ORG/BLK WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) (UNDER RIGHT END OF I/P) PPL PPL 15 16 PPL/WHT WIRE PRESSURE CONTROL SOL RANGE MODE SELECTOR RED WIRE RED/BLK WIRE RESUME/ACCEL SIG SET/COAST SIG SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) SYSTEM GND CLOSURE SIG APP 2 SENS GND APP 1 SENS GND APP 3 SENS GND SENSOR GND TAN WIRE TAN/WHT WIRE TCC BRAKE SW TCC SOL 2-3 SHIFT SOL 1-2 SHIFT SOL TRANS FLUID TEMP (TFT) SENSOR TRANS INPUT SPD SIG CKP SIG OPTICAL SENS GND OPTICAL SENS CAM SIG TRANS OUTPUT TRANSMISSION INPUT SPEED SENSOR VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF I/P) VIN P ONLY VSS VSS HI RESOLUTION SIG VSS INPUT VSS OUTPUT WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

A/C SIG AIR CONDITIONING SYSTEM APP 3 SENS SIG FUEL TEMP SIG IAT SIG B/H BARO SENSOR (VIN F) (UPPER LEFT SIDE OF COWL) BLK WIRE BLK/WHT WIRE BLU WIRE BLU/WHT WIRE BRN WIRE BRN/WHT WIRE DK BLU WIRE DK GRN WIRE ECM I FUSE EGR CONTROL PRESSURE/ BARO SENSOR (VIN P, S) (UPPER LEFT SIDE OF COWL) ENG-I FUSE FUEL HEATER (TOP REAR OF ENGINE) FUEL PUMP OIL PRESSURE SWITCH FUEL PUMP RELAY (RIGHT UPPER COWL) FUEL PUMP/SENDER (IN FUEL TANK) FUSE BLOCK FUSIBLE LINK FUSIBLE LINKS GAUGES FUSE GLOW PLUG CONTROL RELAY (RIGHT REAR TOP OF ENGINE) GLOW PLUG SIG GRY WIRE GRY/BLK WIRE HOT AT ALL TIMES HOT AT ALL TIMES STOP FUSE HOT IN RUN BRAKE FUSE HOT IN RUN, BULB TEST OR START HOT IN START OR RUN GLOW PLUG FUSE IGNITION FEED INSTRUMENT CLUSTER INSTRUMENT CLUSTERS SYSTEM LEFT BANK GLOW PLUGS LT BLU/BLK WIRE LT GRN WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (TURBO ONLY) (LEFT REAR ENGINE COMPT, AT COWL) ORG/ WIRE ORG/BLK WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (PCM) (UNDER RIGHT END OF I/P) PPL PPL 15 16 PPL/WHT WIRE RED WIRE RED/BLK WIRE RIGHT BANK GLOW PLUGS SERVICE ENGINE SOON LAMP TAN WIRE TAN/BLK WIRE TCC/ BRAKE SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) VIN P ONLY WAIT LAMP "SERVICE THROTTLE" LAMP WASTEGATE SOL CTRL EGR VENT SOL CTRL "SERVICE THROTTLE" LAMP WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE