GMC Pickup C2500 (1985-2000) red Wiring diagrams

1 2 3 4 5 6 7 8 9 10 ILLUMINATION GROUND AIR TEMP DR SENSOR MODE SIGNAL BATTERY IGNITION GROUND DEFOGGER ELEMENT BLK WIRE BLOWER FUSE 3 BLOWER MOTOR (UNDER RIGHT SIDE OF DASH) BLOWER RESISTOR (ON BLOWER MOTOR HOUSING) BLOWER SWITCH BRN WIRE DK BLU WIRE DK GRN WIRE FRONT MODE DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) FRONT TEMPERATURE DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) FUSE BLOCK GRY WIRE HIGH BLOWER RELAY (ON TOP OF FRONT A/C- HEATER BLOWER HOUSING) HOT AT ALL TIMES HOT IN RUN HTR A/C FUSE 12 HVAC CONTROL MODULE LT BLU WIRE OFF LO ORG/ WIRE PPL REAR DEFOGGER SYSTEM RECIRC CTRL IGNITION RECIRCULATION DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) RED WIRE TAN WIRE UNDERHOOD FUSE/RELAY CENTER WHT WIRE YEL WIRE

1 2 3 4 5 6 7 8 9 10 ILLUMINATION GROUND A/C DISABLE RECIRC DOOR SIGNAL IGNITION A/C COMPRESSOR CLUTCH A/C COMPRESSOR CLUTCH RELAY (IN UNDERHOOD FUSE/RELAY CENTER) A/C COMPRESSOR CYCLING SWITCH (IN LOW PRESSURE LINE, ON ACCUMULATOR) A/C CTRL A/C HIGH PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C LOW PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C REQ AIR TEMP DR SENSOR MODE SIGNAL A/C SWITCH AUX FAN FUSE AUXILIARY COOLING FAN MOTOR AUXILIARY COOLING FAN RELAY (EXC 4.3L) (IN UNDERHOOD FUSE/RELAY CENTER) BATTERY IGNITION GROUND DEFOGGER ELEMENT BLK WIRE BLK/WHT WIRE BLOWER MOTOR (UNDER RIGHT SIDE OF DASH) BLOWER RESISTOR (ON BLOWER MOTOR HOUSING) BLOWER SWITCH BRN WIRE DIODE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE FRONT RECIRCULATION DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) FUSE BLOCK GRY WIRE HIGH BLOWER RELAY (ON TOP OF FRONT A/C-HEATER HOUSING) HOT AT ALL TIMES HOT AT ALL TIMES UNDERHOOD BLOWER FUSE 3 FUSE BLOCK HOT IN RUN HOT IN RUN OR START HTR A/C FUSE 12 HVAC CONTROL MODULE IGN E FUSE A/C COMP FUSE LT BLU WIRE LT GRN WIRE OFF LO ORG/ WIRE PNK WIRE PPL REAR DEFOGGER SYSTEM RED WIRE SW SIG SW SIG RELAY CTRL TAN WIRE UNDERHOOD FUSE BLOCK VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) WHT WIRE YEL WIRE

A/C COMP FUSE AUX FAN CTRL AUX FAN FUSE AUXILIARY COOLING FAN MOTOR AUXILIARY COOLING FAN RELAY (IN UNDERHOOD FUSE/RELAY CENTER) BLK WIRE DK BLU WIRE DK GRN WIRE FAN REQ HEATER AND A/C CONTROL MODULE HOT AT ALL TIMES HOT IN RUN OR START ORG/ WIRE RECIRCULATION DOOR MOTOR (ON A/C- HEATER HOUSING) RED WIRE RELAY CTRL UNDERHOOD FUSE-RELAY CENTER VEHICLE CONTROL MODULE (LEFT REAR OF ENGINE COMPT)

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 AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BLU/WHT WIRE BRAKE FUSE 18 BRAKE SWITCH ASSEMBLY (ON BRAKE PEDAL BRACKET) BRAKE SWITCH INPUT BRN WIRE BRN/WHT WIRE DATA CLASS II DK BLU WIRE ECM 1 FUSE ECM-B FUSE ECT SENS INPUT ELECTRONIC BRAKE CONTROL MODULE ENG 1 FUSE FRONT WHEEL LOCK FUEL INJECTORS, IGNITION CONTROL MOUDULE, IGNITION COIL FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GAUGES FUSE 4 GRY WIRE GRY/BLK WIRE HEADLAMP, PANEL DIMMER SWITCH PNK WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LEFT REAR SIDE LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MAF SENSOR, HEATED OXYGEN SENSORS MALFUNCTION INDICATOR LAMP MIL CONTROL ORG/ WIRE PCM GROUND PCS SOL HI OUT PCS SOL LO OUT PNK WIRE PPL PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) PPL/WHT WIRE PRESS CTRL HI SOLENOID LO RANGE SIGNAL "A" RANGE SIGNAL "B" RANGE SIGNAL "C" RED WIRE RED/BLK WIRE SENSOR GROUND SENSOR RETURN TAN WIRE TCC PWM SOL TCC PWM SOLENOID THROTTLE POSITION SENSOR (MOUNTED TO SIDE OF THROTTLE BODY) TP SENS INPUT TRANS FLUID TEMP SENSOR TRANS FUSE 20 TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANS RANGE SWITCHES TRANS TEMP SIG IN TRANSFER CASE, AXLE SWITCHES UNDERHOOD FUSE/RELAY CENTER VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR VEHICLE SPEED SENSOR ADAPTOR VSS HI VSS LO YEL WIRE YEL/BLK WIRE

BLK WIRE BLK/WHT WIRE BRN WIRE DATA LINK CONNECTOR (DLC) (LEFT SIDE OF DASH) DK GRN WIRE ELECTRONIC POWER STEERING SYSTEM ENGINE CONTROLS SYSTEM EVO SOL FEED EVO SOL OUT EVO/PASSLOCK MODULE (NEAR DASH AUXILIARY STORAGE COMPARTMENT) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU WIRE NCA WIRE ORG/ WIRE ORG/BLK WIRE PASSLOCK SENSOR (IN STEERING COLUMN, NEAR LOCK CYLINDER) PNK PPL WIRE PNK WIRE PPL RED WIRE RED/WHT WIRE RESISTOR 10 OHMS SEC/STRG FUSE 21 SECURITY INDICATOR SENSOR PASSLOCK GRD SIGNAL STEERING HANDWHEEL SPEED SENSOR (SENSOR GROUND) WHT WIRE YEL WIRE

7.4L A/C COMP FUSE A/C COMPRESSOR CLUTCH RELAY ABS FUSE 4 AUX FAN FUSE RR DEFOG FUSE AUX PWR AUTO HEADLAP FUSE 22 AUXILIARY COOLING FAN RELAY BLK WIRE BLOWER FUSE 3 BLU WIRE BODY CONTROL MODULE (BCM) BRAKE CONTROL MODULE BREAKOUT) BRAKE LAMP RELAY UNDERHOOD FUSE BLOCK BREAKOUT GASOLINE-ENG HARN, BREAKOUT) CAMP/TRAIL FUSE CONN CONVENIENCE CENTER CTSY FUSE 3 DIODE DK BLU/WHT WIRE DRL/FOG FUSE 15 DUAL BATTERY ECM-B FUSE ELECTRONIC BRAKE CONTROL MODULE FROM LT GRN 6-PIN WIRE FRONT REAR DOME DOME LAMPS LAMPS FUEL PUMP OIL PRESSURE SWITCH FUEL PUMP RELAY UNDERHOOD FUSE BLOCK FUSIBLE LINK (5 GA-RUST) GARAGE OVERHEAD DOOR CONSOLE OPENER READING LAMPS GENERATOR (BASE) GENERATOR (UPLEVEL) HEADLAMP HEADLAMP AND PANEL DIMMER SWITCH HEADLAMP CONTROL MODULE HEATER MIRROR RELAY HIGH BLOWER MOTOR RELAY HORN FUSE HORN RELAY UNDERHOOD LAMP UNDERHOOD FUSE BLOCK HTD MIR FUSE HVAC CONTROL MODULE I/P COMPARTMENT BOX LAMP I/P FUSE BLOCK INFLATABLE RESTRAINT SWITCH BREAKOUT) INTERIOR LAMP CONTROL MODULE LEFT BATTERY (DIESEL) LEFT CARGO COURTESY LAMP LAMP SWITCH LEFT RIGHT VANITY VANITY MIRROR MIRROR LUXURY ONLY MEGA FUSE BLOCK NCA WIRE OR BLK 8-PIN IN-LINE WIRE ORG/ WIRE OVERHEAD FRONT CONSOLE DOME READING LAMP LAMPS PANEL DIMMER SWITCH PICKUP ONLY PK LPS FUSE 9 POWER OUTSIDE REARVIEW MIRROR SWITCH POWERTRAIN CONTROL MODULE (DIESEL) RED WIRE REMOTE BATTERY STUD RIGHT BATTERY RIGHT COURTESY LAMP RIGHT FRONT DOOR COURTESY LAMP SECURITY/ STRG FUSE 21 SEO FUSE SINGLE BATTERY (BASE) SINGLE BATTERY (UPLEVEL) SPARE POWER SOURCE STARTER MOTOR SOLENOID STOP FUSE 2 LIGHTING FUSE 8 TO FUSIBLE LINK (DIAGRAM 5 OF 5) TO UNDERHOOD FUSE BLOCK (DIAGRAM 2 OF 5) UNDERHOOD FUSE BLOCK VEHICLE CONTROL MODULE (GASOLINE) W/O REAR AUXILIARY HEATER OR A/C W/O RKE YEL WIRE

AUDIO ALARM MODULE AUDIO AMPLIFIER AUTOMATIC AUTOMATIC TRANSFER CASE AUTOMATIC TRANSFER CASE CONTROL MODULE BASE AUX/PWR FUSE 7 BASE CARGO DOOR LUXURY ONLY BATTERY FUSE 7 BLK WIRE CIG LTR FUSE 13 CIGAR LIGHTER COLUMN HARNESS BREAKOUT) CONVENIENCE CENTER DATA LINK CONNECTOR DOOR REAR LIFTGATE LOCK DOOR RELEASE CONTROL LOCK RELAY MODULE SWITCH ELECTRIC FROM UNDERHOOD FUSE BLOCK (DIAGRAM 1 OF 5) I/P CLUSTER BREAKOUT) I/P FUSE BLOCK LEFT FRONT DOOR LOCK SWITCH LIFTGATE RELEASE SWITCH LUXURY LEVEL LUXURY ONLY NON- BASE ORG/ WIRE OTHERS PICKUP PICKUPS W/O RKE POWER OUTLET BREAKOUT) PWR-ACCY CIRCUIT BREAKER A (REGULAR CAB/EXTENDED CAB/LUXURY) RADIO RADIO BATT FUSE 19 REAR AUXILIARY POWER CONNECTOR (LUXURY) REAR CONSOLE AUXILIARY POWER CONNECTOR (LUXURY) RED WIRE REMOTE CONTROL DOOR LOCK RECEIVER RIGHT FRONT LEFT FRONT POWER POWER LUMBAR LUMBAR SEAT SWITCH SEAT SWITCH RIGHT LUMBAR POWER SEAT RIGHT LUMBAR POWER SEAT SWITCH RIGHT POWER SEAT ADJUSTER SWITCH SEAT LUMBAR SWITCH BREAKOUT) STEERING COLUMN HARNESS BREAKOUT) STOP LAMP SWITCH STOP/HAZ FUSE 1 SUBURBAN/ UTILITY SWITCH T CASE FUSE 2 TO UNDERHOOD FUSE BLOCK (DIAGRAM 3 OF 5) TRANSFER CASE CONTROL MODULE TURN/ HAZARD SWITCH UNDERHOOD FUSE BLOCK VEHICLE INTERFACE UNIT W/ RKE W/BENCH SEAT

A/T M/T AIR BAG FUSE 10 BODY CONTROL MODULE BODY REAR RADIO CONTROL STEREO MODULE CONTROLLER BRN WIRE CLUTCH PEDAL PARK/NEUTRAL POSITION POSITION SWITCH SWITCH COLUMN HARN BREAKOUT) PNK WIRE CONVENIENCE CENTER CRANK FUSE 8 DAYTIME RUNNING LAMPS MODULE DK BLU WIRE ELECTROCHROMIC REARVIEW MIRROR W/ COMPASS FROM CONVENIENCE CENTER BREAKOUT) FROM IGNITION SWITCH (DIAGRAM 3 OF 5) FROM UNDERHOOD FUSE BLOCK GAS DIESEL GAUGES FUSE 4 HEADLAMP, PANEL DIMMER SWITCH I/P FUSE BLOCK IGN A FUSE 6 IGN B FUSE 5 IGNITION SWITCH INFLATABLE RESTRAINT I/P MODULE SWITCH (PICKUP) INFLATABLE RESTRAINT SENSING, DIAGNOSTIC MODULE INTERIOR LAMP CONTROL MODULE OR REMOTE CONTROL DOOR LOCK RECEIVER LOCK OFF LUXURY LUXURY ONLY M/T M/T A/T ORG/ WIRE OTHERS PNK WIRE POWER WINDOW MASTER SWITCH PPL PWR WDO CIRCUIT BREAKER RADIO BATT FUSE 17 REAR WINDOW LOCKOUT SWITCH (4-DR) RED WIRE RR WIPER FUSE 23 TRANS FUSE 20 WIPER FUSE 11 RUN WIRE STARTER RELAY TO UNDERHOOD FUSE BLOCK (DIAGRAM 4 OF 5) PNK WIRE TO UNDERHOOD FUSE BLOCK (DIAGRAM 5 OF 5) TRANSFER CASE SELECT SWITCH TURN B/U FUSE 16 UNDERHOOD FUSE BLOCK VEHICLE RIGHT FRONT INTERFACE POWER UNIT WINDOW SWITCH (2 DR, UTILITY) VEHICLE SPEED SENSOR BUFFER (DIESEL) W/O RKE W/ RKE WHT WIRE WINDSHIELD WIPER INSTRUMENT MOTOR CLUSTER MODULE YEL WIRE

AUTOMATIC TRANSFER CASE CONTROL MODULE AUTOMATIC TRANSFER CASE ONLY AUTOMATIC TRANSFER CASE SELECT SWITCH AUXILIARY AUXILIARY TEMPERATURE HIGH BLOWER DOOR MOTOR MOTOR RELAY AUXILIARY BATTERY AUXILIARY BATTERY RELAY (LEFT REAR OF ENGINE COMPT) AUXILIARY HEATER/ A/C CONTROL LOGIC MODULE AUXILIARY HEATER/ A/C CONTROL MODULE (FRONT) AUXILIARY HEATER/ A/C CONTROL MODULE (REAR) AUXILIARY MEDIUM BLOWER MOTOR RELAY BLK WIRE BLK/RED WIRE BLU WIRE BRAKE FUSE 18 BREAKOUT) BRN WIRE COLUMN HARNESS BREAKOUT) CONVENIENCE CENTER CROSSBODY HARN, 20 CM FROM SDM BREAKOUT) CRUISE CONTROL MODULE (GAS ONLY) CRUISE CONTROL SWITCH CRUISE FUSE 6 ELECTRONIC BRAKE CONTROL MODULE FROM BREAKOUT TO GROUND AT LEFT SIDE FRAME RAIL, NEAR CROSSMEMBER) FROM IGNITION SWITCH (DIAGRAM 3 OF 5) FROM UNDERHOOD FUSE BLOCK (DIAGRAM 1 OF 5) FROM UNDERHOOD FUSE BLOCK (DIAGRAM 3 OF 5) FRONT AXLE ACTUATOR FRONT HEATED SEATS FUSE FUSE 24 FUSIBLE LINK GAS, BASE MODELS DIESEL GAS, EXCEPT BASE MODELS HTR A/C FUSE 12 HVAC CONTROL MODULE I/P FUSE BLOCK LEFT FRONT FENDER) LEFT FRONT HEATED SEAT MODULE LEFT REAR HEATED SEAT MODULE LEFT REAR HEATED SEAT SWITCH LUXURY LEVEL LUXURY MODELS MODE DOOR MOTOR MOTOR RELAYS) ORG/ WIRE REAR HEATED SEATS FUSE REAR HEATER REAR HEATER W/ W/ REAR CARGO LIFT- HEATER DOORS GATE ONLY RECIRCULATION TEMPERATURE DOOR DOOR MOTOR MOTOR RED WIRE RESTRAINT SWITCH BREAKOUT) RIGHT FRONT HEATED SEAT MODULE RR HVAC FUSE 5 SEATS FUSE STOP LAMP SWITCH SUBURBAN, UTILITY ONLY TRANSFER SPARE CASE POWER SWITCH SOURCE UNDERHOOD FUSE BLOCK VEHICLE CONTROL MODULE (GAS ONLY) W/ REAR DEFROST

BLK WIRE BLU WIRE BRN WIRE CTSY FUSE 3 DOWN GRY WIRE HOT AT ALL TIMES I/P FUSE BLOCK ILLUM- NATION LAMP LEFT LEFT POWER OUTSIDE REARVIEW MIRROR LEFT/ RIGHT MOTOR LT (OR LT GRN WIRE ORG/ WIRE POWER OUTSIDE REARVIEW MIRROR SWITCH PPL/WHT WIRE RED WIRE RIGHT RIGHT POWER OUTSIDE REARVIEW MIRROR UP/ DOWN MOTOR YEL WIRE