GMC Pickup C2500 (1985-2000) brn Wiring diagrams

AUX FUSE 22 AUXILIARY LEAD (TAPED TO HARNESS) BACK-UP LIGHTS CIRCUIT BLK WIRE BLU WIRE BRN WIRE CARGO LAMP CARGO LAMP SWITCH CENTER HIGH MOUNT STOP LAMP CHMSL LAMP (2 BULBS) CRUISE CONTROL SYSTEM CTSY FUSE 3 DK BLU WIRE DK GRN WIRE GRN WIRE GRY WIRE HAZARD NORMAL HEADLAMP, PANEL DIMMER SWITCH HEADLIGHTS SYSTEM HOT AT ALL TIMES HOT AT ALL TIMES UNDER- HOOD FUSE- RELAY CENTER (LEFT REAR OF ENGINE COMPT.) HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK INSTRU- MENT CLUSTER RIGHT TURN INDIC LEFT LEFT FRONT MARKER LAMP LEFT FRONT PARK/ TURN LAMPS LEFT SPOTLAMP ASSEMBLY (POLICE PACKAGE) LEFT TAIL/ STOP/ TURN LAMP DK DK LEFT TURN INDIC LICENSE LICENSE LAMP LAMPS LT BLU WIRE LT GRN WIRE MAXI FUSE 2 NCA WIRE OFF ORG/ WIRE PARK PARK LPS FUSE 9 PICKUP PNK WIRE POLICE PACKAGE (1999 ONLY) PPL REAR CLEARANCE LAMPS CIRCUIT RED WIRE RHEO- STAT RIGHT RIGHT FRONT MARKER LAMP RIGHT FRONT PARK/ TURN LAMPS RIGHT SPOTLAMP ASSEMBLY (POLICE PACKAGE) RIGHT TAIL/ STOP/ TURN LAMP ROOF MARKER LAMPS STOP- LAMP RELAY (EXCEPT SUBUR- BAN/ UTILITY) STOP/ HAZ FUSE 1 STOPLAMP SWITCH (TOP OF BRAKE PEDAL) SUBURBAN/ UTILITY TRAILER TOW CONNECTOR TURN B/U FUSE 16 TURN PWR HAZ PWR FLSHR OUT GND TURN/ HAZARD SWITCH TURN/HAZARD FLASHER (ON CONVENIENCE CENTER) UNDER- HOOD FUSE RELAY CENTER (LEFT REAR OF ENGINE COMPT.) W/ DUAL REAR WHEELS W/ STEP BUMPER W/O STEP BUMPER WHT WIRE YEL WIRE

BLK WIRE BLK/WHT WIRE BRN WIRE CHASSIS CAB CONVENIENCE CENTER DATA LINK CONNECTOR ENDGATE ENDGATE CLEARANCE LAMPS EVRV ELECTRONIC VACUUM REGULATOR VALVE SOLENOID FUEL PUMP FUEL PUMP RELAY HEAVY DUTY TRAILER HOT FUEL HANDLING MODULE KNOCK SENSOR MODULE LEFT CARGO DOOR DEFOGGER GRID LEFT DOOR CONTACT SWITCH LEFT FRONT CLEARANCE LAMP LEFT LICENSE LAMP LEFT REAR CENTER TAIL, STOP, HIGH LICENSE, MOUNT TURN AND STOPLAMP BACKUP LAMPS LEFT REAR CLEARANCE LAMP LEFT REAR FENDER LEFT REAR TAIL, STOP, TURN AND BACKUP LAMPS LEFT TAIL/ STOP, TURN AND BACKUP LAMP ORN/ PARK/ NEUTRAL POSITION SWITCH PICKUP (W/O DUAL REAR WHEELS), SUBURBAN AND UTILITY PICKUP WITH DUAL REAR WHEELS POWERTRAIN CONTROL MODULE (PCM) REAR DOOR W/ AUXILLIARY JAMB SWITCH HEATER, AIR CONDITIONING REAR ENDGATE LIFTGATE WINDOW WINDOW DEFOGGER RELEASE GRID SOLENOID REAR WIPER MOTOR MODULE RIGHT CARGO DOOR DEFOGGER GRID RIGHT DOOR CONTACT SWITCH RIGHT FRONT CLEARANCE LAMP RIGHT GAS STRUT CYLINDER RIGHT LEFT LICENSE LICENSE LAMP LAMP RIGHT LICENSE LAMP RIGHT REAR CLEARANCE LAMP RIGHT REAR FENDER RIGHT REAR TAIL, STOP, LICENSE, TURN AND BACKUP LAMPS RIGHT REAR TAIL, STOP, TURN AND BACKUP LAMPS RIGHT TAIL/ STOP, TURN AND BACKUP LAMP SUBURBAN, UTILITY NON-BASE VEHICLE SUBURBAN, UTILITY W/ AUTOMATIC TRANSMISSIONS SUBURBAN/ UTILITY TAN WIRE TAN/WHT WIRE TEMPER- ATURE BLOWER MODE MODE DOOR MOTOR DOOR (REAR) RELAY MOTOR TRAILER) VEHICLE SPEED SENSOR BUFFER W/ REAR AUXILLIARY HEATER ONLY W/HD AUTOMATIC TRANSMISSION) WHT WIRE WHT/ BLK WIRE WITH ENDGATE

BLK WIRE BRN WIRE BULB CHECK DAYTIME RUNNING LAMP INDICATOR DAYTIME RUNNING LAMPS MODULE (BEHIND LEFT SIDE OF I/P) DAYTIME RUNNING LAMPS RELAY (ENGINE COMPARTMENT FRONT PLENUM PANEL) DK BLU/WHT WIRE DRL FUSE FUSE BLOCK GRN WIRE HEAD PARK HEADLAMP DIMMER SWITCH HEADLIGHT SWITCH ASSEMBLY HI BEAM INDICATOR HOT AT ALL TIMES HOT IN RUN HOT IN RUN, BULB TEST OR START GAUGES FUSE HTR A/C FUSE IGNITION LAMP FEED HI BEAM FEED HI BEAM INDICATOR OUTPUT TO RELAY GROUND INSTRUMENT CLUSTER LEFT HIGH BEAM HEADLAMP LEFT LOW BEAM HEADLAMP LT GRN WIRE LT GRN/BLK WIRE LT LT OFF OFF HEAD ORG/ WIRE PARK PARK BRAKE WARNING SWITCH (AT PARK BRAKE, UNDER LEFT SIDE OF I/P) PICKUP ONLY PNK/BLK WIRE RIGHT HIGH BEAM HEADLAMP RIGHT LOW BEAM HEADLAMP SUBURBAN, UTILITY ONLY TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE

BLK WIRE BRN WIRE BULB CHECK DAYTIME RUNNING LAMP INDICATOR DAYTIME RUNNING LAMPS MODULE (BEHIND LEFT SIDE OF I/P) DAYTIME RUNNING LAMPS RELAY (ENGINE COMPARTMENT FRONT PLENUM PANEL) DK BLU/WHT WIRE DRL FUSE FUSE BLOCK GRN WIRE HEAD PARK HEADLAMP DIMMER SWITCH HEADLIGHT SWITCH ASSEMBLY HI BEAM INDICATOR HI LO HOT AT ALL TIMES HOT IN RUN HOT IN RUN, BULB TEST OR START GAUGES FUSE HTR A/C FUSE IGNITION LAMP FEED HI BEAM FEED HI BEAM INDICATOR OUTPUT TO RELAY GROUND INSTRUMENT CLUSTER LEFT HEADLAMP ASSEMBLY LT GRN WIRE LT GRN/BLK WIRE LT LT OFF OFF HEAD ORG/ WIRE PARK PARK BRAKE WARNING SWITCH (AT PARK BRAKE, UNDER LEFT SIDE OF I/P) PICKUP ONLY PNK/BLK WIRE RIGHT HEADLAMP ASSEMBLY SUBURBAN, UTILITY ONLY TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE

BLK WIRE BRN WIRE CONVENIENCE CENTER DK BLU WIRE FOG LAMP ON INDICATOR FOG LAMP RELAY (BEHIND LEFT SIDE OF I/P) FOG LAMP SWITCH SOLID STATE SWITCH FUSE BLOCK GRN WIRE GRY WIRE HEADLAMP DIMMER SWITCH HEADLIGHT SWITCH ASSEMBLY HI BEAM INDICATOR HI LO HOT AT ALL TIMES HOT AT ALL TIMES ACC-BATT CIRCUIT BREAKER ILLUM LAMP LEFT LOW BEAM HEAD- LAMP LT GRN WIRE LT INSTRUMENT CLUSTER LT LT OFF OFF HEAD HEAD PARK ORG/BLK WIRE PARK PNL LPS FUSE PPL PPL PPL RIGHT FOG LAMP LEFT FOG LAMP RIGHT HIGH BEAM HEAD- LAMP LEFT HIGH BEAM HEAD- LAMP RIGHT LOW BEAM HEAD- LAMP TAN WIRE VARIABLE VOLTAGE W/ HEADLIGHT SWITCH IN PARK OR HEAD, RHEOSTAT ADJUSTED WHT WIRE YEL WIRE

A/T ACCY AIR BAG ANTI-LOCK BRAKES ANTI-LOCK BRAKES SYSTEM BLK WIRE BLK/WHT WIRE BRAKE PRESSURE WARNING SWITCH (ON REAR OF BRAKE PRESSURE MODULATOR VALVE BODY) BRAKE/ BRN WIRE BRN/WHT WIRE BULB TEST CHECK GAUGES CHECK GAUGES LAMP DRIVER CONVENIENCE CENTER (BEHIND LEFT SIDE OF I/P) DAYTIME RUNNING LAMPS DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ELECTRONIC PRNDL DISPLAY MODULE ENG-I MINI FUSE ENGINE CONTROLS SYSTEM ENGINE CONTROLS SYSTEM SOUND SYSTEMS ENGINE CONTROLS SYSTEM ENGINE COOLANT TEMPERATURE SENDER (FRONT OF LEFT CYLINDER HEAD) FUEL GAUGE FUEL PUMP, SENDER (IN FUEL TANK) GAUGES FUSE 4 GEN WAIT TO GRY WIRE HEADLIGHTS SYSTEM HEADLIGHTS SYSTEM (DRL) HI BEAM HOT IN RUN OR START I/P FUSE BLOCK (BEHIND LEFT SIDE OF I/P) IGNITION SWITCH ILLUM INSTRUMENT CLUSTER LEFT TURN LOCK OFF W/ DRL ONLY LOW COOLANT LOW COOLANT LEVEL SENDER (IN COOLANT RESERVOIR) LOW ENGINE COOLANT LEVEL INDICATOR MODULE (UNDER CENTER OF I/P) LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE M/T PNK WIRE NCA WIRE OIL PRESS OIL PRESSURE SWITCH/SENDER (LEFT REAR TOP OF ENGINE) PARK BRAKE WARNING SWITCH (LEFT END OF I/P) PNK WIRE PPL PPL/WHT WIRE RIGHT TURN RUN WIRE SAFETY BELT SERVICE ENGINE SOON SERVICE THROTTLE SOON UP- SHIFT SPEED- OMETER STARTING/CHARGING SYSTEM SUPPLEMENTAL RESTRAINTS SYSTEM TACH VOLT- METER TAN WIRE TAN/ WHT WIRE TAN/BLK WIRE TAN/WHT WIRE TEMP GAUGE TRANS FUSE 20 TRANSMISSSION RANGE SELECTOR TRUNK, TAILGATE, FUEL DOORS SYSTEM TRUNK/TAIL- GATE/FUEL DOORS SYSTEM UNDERHOOD FUSE/RELAY CENTER (LEFT REAR OF ENGINE COMPT) VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT END OF I/P) W/O DRL ONLY WARNING SYSTEMS WATER IN FUEL WATER-IN FUEL SENSOR (TOP REAR OF ENGINE) WHT TAN/ WIRE WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

BLK WIRE BRN WIRE ENDGATE MARKER LAMPS FRONT MARKER, PARK/TURN LAMPS FUSE BLOCK- I/P HEAD OFF HEADLIGHT SWITCH ASSEMBLY HOT AT ALL TIMES LEFT FRONT CLEARANCE LAMP LEFT REAR CLEARANCE LAMP LEFT REAR FENDER ORG/ WIRE PARK PARK LPS FUSE RIGHT FRONT CLEARANCE LAMP RIGHT REAR CLEARANCE LAMP RIGHT REAR FENDER TAIL/STOP/TURN, LICENSE LAMPS) TRAILER TOW

7.4L ONLY A/C ON SIGNAL IN AIR CONDITION- ING SYSTEM BLK WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE COOLANT TEMP. SENSOR CRUISE CONTROL SYSTEM CRUISE IND REG GRD DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE DLC SERIAL DATA DLC THROTTLE POSITION SENSOR IN LO SIDE INJ A ECM-I MINI FUSE EGR VALVE SOLENOID (4.3L ONLY) (RIGHT SIDE OF ENGINE) EGR VALVE SOLENOID SHIFT LAMP CONTROL ELEC FUEL PUMP IN MAP SENSOR IN ENG-I MINI FUSE EVAP CANISTER PURGE CTRL EVAPORATIVE CANISTER PURGE SOLENOID (7.4L ONLY) (RIGHT SIDE OF ENGINE) FUEL PUMP RELAY CTRL GRY WIRE HOT IN RUN OR START IDLE AIR CONTROL UNIT (RIGHT REAR OF TBI UNIT) IDLE SPEED CONTROL IGNITION BYPASS IGNITION CONTROL (IC) VSS BUFFER SIGNAL VSS BUFFER SIGNAL KNOCK SENSOR IN PINTLE POSITION SIGNAL LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE MIL INDICATOR CTRL ORG/ WIRE OXYGEN SENSOR LO PNK WIRE POWERTRAIN CONTROL MODULE (UNDER RIGHT SIDE OF I/P) PPL PPL 1 2 3 4 PPL/WHT WIRE RED/BLK WIRE TAN WIRE TAN/BLK WIRE TAN/WHT WIRE THROTTLE BODY FUEL INJECTOR #1 (TOP OF THROTTLE BODY UNIT) THROTTLE BODY FUEL INJECTOR #2 (TOP OF THROTTLE BODY UNIT) UNDERHOOD FUSE/RELAY CENTER (LEFT REAR OF ENGINE COMPT) WHT DK GRN/ WIRE WHT WIRE WHT/BLK WIRE YEL WIRE

4.3L ONLY 423 3 121 PNK WIRE ACCY BLK WIRE BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (FRONT OF ENGINE) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (BEHIND LEFT SIDE OF I/P) IGNITION COIL (CENTER REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (4.3L ONLY) (REAR OF ENGINE) KNOCK SENSOR (RIGHT SIDE OF ENGINE, BELOW EXHAUST MANIFOLD) LINEAR EGR VALVE (7.4L ONLY) (RIGHT SIDE TOP OF ENGINE) LOCK OFF LT GRN WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (RIGHT REAR TOP OF ENGINE) NCA WIRE ORG/ WIRE PNK WIRE PPL PPL 1 2 3 4 PPL/WHT WIRE RED/BLK WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE THROTTLE POSITION SENSOR (RIGHT SIDE OF THROTTLE BODY) UPSHIFT LAMP WHT WIRE WHT/BLK WIRE YEL WIRE

4.3L ONLY BLK WIRE BLK/WHT WIRE BRN WIRE DATA LINK CONNECTOR (UNDER LEFT SIDE OF I/P) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM-B MINI FUSE FUEL PUMP AND SENDER FUEL PUMP OIL PRESSURE SWITCH (TOP REAR OF ENGINE NEAR DISTRIBUTOR) FUEL PUMP PRIME CONN- ECTOR FUEL PUMP RELAY (UNDERHOOD FUSE/RELAY CENTER) GRY WIRE HEATED OXYGEN SENSOR (IN EXHAUST Y-PIPE) HOT AT ALL TIMES IDLE SPEED CONTROL ACTUATOR SOLENOID (7.4L ONLY) (SIDE OF THROTTLE BODY UNIT) INSTRUMENT CLUSTER LT GRN/BLK WIRE OIL PRESS IN ORG/ WIRE PNK WIRE PPL PPL/WHT WIRE RED WIRE TACH IN TAN WIRE UNDERHOOD FUSE/RELAY CENTER (LEFT REAR OF ENGINE COMPT) VEHICLE SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF I/P) VSS IN WHT WIRE WHT/BLK WIRE