GMC Pickup C3500 (1985-2000) blk/wht Wiring diagrams

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID 3-2 CTRL SOLENOID 3-2 DOWNSHIFT SOL AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BLU WIRE BRAKE FUSE 18 BRAKE SWITCH INPUT BRN WIRE BRN/WHT WIRE DASH FUSE BLOCK DATA CLASS II DK BLU WIRE ECM 1 FUSE ECM-B FUSE ECT SENS INPUT ELECTRONIC BRAKE CONTROL MODULE ENG 1 FUSE ENGINE COOLANT TEMP SENSOR (TOP RIGHT FRONT OF ENGINE) FRONT WHEEL LOCK FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GAUGES FUSE 4 GRY WIRE GRY/BLK WIRE HOT AT ALL TIMES HOT IN OFF, RUN OR START HOT IN RUN HOT IN RUN OR START 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 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 STOPLAMP SWITCH (ON BRAKE PEDAL BRACKET) TAN WIRE TAN/BLK WIRE TCC PWM SOL TCC PWM SOLENOID TCC SOL TCC 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 CIRCUIT PNK WIRE TRANSFER CASE, AXLE SWITCHES UNDERHOOD FUSE/RELAY CENTER VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR VEHICLE SPEED SENSOR ADAPTOR VSS HI VSS LO WHT WIRE YEL WIRE YEL/BLK WIRE

1 2 3 4 5 6 7 8 9 10 ILLUMINATION GROUND A/C DISABLE AUX FAN CTRL 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 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 FUSE 3 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 MODE DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) FUSE BLOCK GRY WIRE GRY/BLK WIRE HIGH BLOWER RELAY (ON TOP OF FRONT A/C-HEATER HOUSING) HOT AT ALL TIMES HOT AT ALL TIMES UNDERHOOD FUSE-RELAY CENTER 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-RELAY CENTER VALVE CTRL AIR TEMP DR SENSOR MODE SIGNAL A/C SWITCH VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) WATER VALVE (SUBURBAN, UTILITY, CREW CAB ONLY) (RIGHT CENTER OF INTAKE AREA) WHT WIRE YEL 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

39 1807 PNK PPL WIRE BLK WIRE BLK/WHT WIRE BRN WIRE DATA LINK CONNECTOR (DLC) (UNDER LEFT SIDE OF DASH, LEFT OF STEERING COLUMN) PPL DIESEL DK GRN WIRE DK GRN/WHT WIRE ELECTRONIC VARIABLE ORIFICE (EVO)/ PASSLOCK MODULE (UNDER CENTER OF DASH) EVO SOLENOID OUT EVO FEED SWS POSIT SIG VSS SIGNAL INPUT GAS GAUGES FUSE 4 GROUND IGNITION DATA SENSOR RETURN 5 VOLT REF BATTERY GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) LT BLU WIRE ORG/ WIRE ORG/BLK WIRE PNK WIRE SECURITY/STRG FUSE 21 SENSOR RETURN STEERING ASSIST CONTROL SOLENOID (PART OF POWER STEERING PUMP) STEERING HANDWHEEL SPEED SENSOR (ON STEERING COLUMN, NEAR FIREWALL) STEERING VOLT WHEEL POSIT REF SIGNAL VEHICLE CONTROL MODULE (ON LEFT SIDE OF ENGINE COMPARTMENT) VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF DASH) VSS SIG OUT WHT WIRE

4.3L A/C COMPRESSOR CLUTCH A/C COMPRESSOR CYCLING SWITCH A/C HIGH PRESSURE (NOT CUTOUT USED) SWITCH AIR REACTION INJECTION (SECONDARY) WATER PUMP VALVE (7.4L ONLY) BALANCE FUEL FUEL PUMP GAGE BALANCE SENDER MODULE BLK WIRE BLK/WHT WIRE BLOWER MOTOR BRAKE PRESSURE WARNING SWITCH CRUISE INSTRUMENT CONTROL CLUSTER MODULE DATA LINK CONNECTOR DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE EVAPORATIVE EMISSIONS PURGE VACUUM SOLENOID SWITCH EXCEPT 4.3L FRONT AXLE ACTUATOR FRONT MODE DOOR MOTOR FRONT TEMPERATURE DOOR MOTOR FUEL PUMP AND SENDER GASOLINE HEATED OXYGEN SENSOR BANK 1 SENSOR 1 HEATED OXYGEN SENSOR BANK 1 SENSOR 2 HEATED OXYGEN SENSOR BANK 2 SENSOR 1 HEATED OXYGEN SENSOR BANK 2 SENSOR 2 HIGH A/C PRESSURE CUTOUT SWITCH HIGH BLOWER MOTOR RELAY IGNITION COIL MODULE MASS AIRFLOW SENSOR PARK/ NEUTRAL POSITION SWITCH POWER STEERING CONTROL MODULE RECIRCULATION DOOR MOTOR STARTER RELAY STOPLAMP RELAY TRANSFER CASE RELAY TRANSFER CASE RELAY BREAKOUT) UNDER- HOOD LAMP UNDERHOOD FUSE- RELAY CENTER A/C COMPRESSOR CLUTCH RELAY UNDERHOOD FUSE-RELAY CENTER VEHICLE CONTROL MODULE VEHICLE UNDER- SPEED HOOD SENSOR REEL (BLUNT CUT) LAMP W/ DUAL TANKS W/O DUAL TANKS (EXCEPT 4.3L) UNDERHOOD FUSE- RELAY CENTER FUEL PUMP RELAY

4.3L ONLY BALANCE FUEL GAGE SENDER BENCH OTHERS SEAT BLK WIRE BLK/WHT WIRE CENTER HIGH MOUNT STOP LAMP CONVENIENCE CENTER CONVENIENCE CENTER (UNDER LEFT SIDE OF I/P) DATA LINK CONNECTOR DIESEL DOOR LOCK RELAY ELECTROCHROMIC REARVIEW MIRROR W/ COMPASS FOUR-WHEEL DRIVE INDICATOR LAMP FUEL GAGE SENDER FUEL PUMP AND SENDER FUEL PUMP BALANCE MODULE INSTRUMENT CLUSTER INTERIOR LAMP CONTROL MODULE LEFT CLEARANCE LAMP LEFT FRONT POWER WINDOW LOCK SWITCH LEFT ILLUMINATED VANITY MIRROR LEFT POWER LUMBAR SUPPORT MOTOR LEFT REAR REAR POWER WINDOW WINDOW LOCKOUT SWITCH SWITCH MASS AIRFLOW SENSOR POWER AMPLIFIER POWER AMPLIFIER RELAY POWER FUEL STEERING PUMP CONTROL RELAY MODULE POWER OUTSIDE REARVIEW MIRROR SWITCH POWERTRAIN CONTROL MODULE REMOTE CONTROL DOOR LOCK RECEIVER RIGHT CLEARANCE LAMP RIGHT FRONT POWER WINDOW SWITCH RIGHT ILLUMINATED VANITY MIRROR RIGHT POWER LUMBAR SUPPORT MOTOR RIGHT POWER POWER LEFT POWER LUMBAR MOTOR SEAT RIGHT REAR POWER WINDOW SWITCH ROOF MARKER LAMPS SEAT BELT SWITCH TAN/WHT WIRE TRANSFER CASE MODE SELECTOR ILLUMINATION LAMP UNDER HOOD FUSE-RELAY CENTER VEHICLE SPEED SENSOR BUFFER WHT/ BLK WIRE

AUXILIARY HEATER- A/C LOGIC MODULE BALANCE FUEL PUMP BLK WIRE BLK/WHT WIRE CENTER HIGH MOUNT STOPLAMP CHASSIS CAB, HEAVY DUTY DOOR CONTACT BUTTON DOOR LOCK CONTROL MODULE EXCEPT CHASSIS CAB, HEAVY DUTY FRONT AUXILIARY HEATER-A/C CONTROL MODULE FRONT REAR DOME DOME LAMP LAMP FUEL LIFT PUMP INFLATABLE RESTRAINT FRONT END SENSOR INFLATABLE RESTRAINT SENSING AND DIAGNOSTIC MODULE LEFT CARGO DOOR DEFOGGER GRID LEFT LEFT REAR FRONT CLEARANCE CLEARANCE LAMP LAMP LEFT REAR FENDER LEFT REAR TAIL, STOP, LICENSE, TURN, BACKUP LAMPS LEFT REAR TAIL, STOP, TURN, LEFT BACKUP LICENSE LAMP LAMPS LEFT TAIL, STOP, LEFT TURN, LICENSE BACKUP LAMPS LAMP OVERHEAD CONSOLE LAMPS PICKUP W/ DUAL REAR WHEELS REAR AUXILIARY HEATER-A/C CONTROL MODULE REAR AUXILIARY MODE DOOR MOTOR REAR AUXILIARY TEMP DOOR MOTOR REAR BLOWER MOTOR REAR LIFTGATE WINDOW DEFOGGER GRID REAR WIPER MOTOR MODULE RIGHT CARGO DOOR DEFOGGER GRID RIGHT ENDGATE LICENSE MARKER LAMP LAMPS RIGHT LICENSE LAMP RIGHT REAR DOOR JAMB SWITCH RIGHT REAR FENDER RIGHT REAR TAIL, STOP, LICENSE, TURN, BACKUP LAMPS RIGHT REAR TAIL, STOP, TURN, BACKUP LAMPS RIGHT RIGHT REAR FRONT CLEARANCE CLEARANCE LAMP LAMP RIGHT TAIL, STOP, TURN, BACKUP LAMPS SUBURBAN/ UTILITY TRAILER GROUND (TAPED BACK) UTILITY ONLY W/ DUAL TANKS WHT WIRE

1134 1134 39 10 10 PARK BRAKE SIG IND BULB CHK IGNITION LAMP FEED PNK WIRE 33 33 BRAKE IND CTRL BRAKE WARN IN 592 592 150 DRL RELAY CTRL BLK WIRE BLK/WHT WIRE BRN WIRE BULB TEST CONVENIENCE CENTER (UNDER LEFT SIDE OF DASH) DAYTIME RUNNING LAMP MODULE (BEHIND LEFT SIDE OF DASH) DAYTIME RUNNING LAMPS RELAY DIODE 203 DRL INDICATOR DRL-FOG FUSE 15 FOG LAMP RELAY FOG LAMP SWITCH GAUGES FUSE 4 GRN WIRE GROUND GRY WIRE HEAD OFF PARK HEAD- LAMP DIMMER SWITCH HEADLAMP, PANEL DIMMER SWITCH HIGH BEAM INDICATOR HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (LEFT SIDE OF DASH, IGNITION SWITCH ILLUM LAMP INSTRUMENT CLUSTER INSTRUMENT CLUSTER SYSTEM (BRAKE WARNING INDICATOR) LEFT FOG LAMP LEFT HEAD- LAMP RIGHT HEAD- LAMP LIGHTING FUSE 8 LOCK OFF LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE OFF ON INDICATOR ORG/ WIRE PARK BRAKE WARNING SWITCH PK LPS FUSE 9 PNK WIRE PPL RED WIRE RIGHT FOG LAMP RUN WIRE TAN WIRE TAN/WHT WIRE UNDERHOOD FUSE BLOCK (LEFT REAR OF ENGINE COMPT) W/ FOG LAMPS WHT WIRE YEL WIRE

260 (CROSS BODY HARNESS, BELT SWITCH BREAKOUT) BLK (OR BLK/WHT) WIRE BLK WIRE BLK/WHT WIRE CIG LTR FUSE 13 CONVENIENCE CENTER (LEFT SIDE OF DASH) DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) DOOR LOCK CONTROL MODULE (FRONT OF LEFT REAR WHEELWELL) DOOR LOCK RELAY (UNDER CENTER OF DASH, NEAR REMOTE CONTROL DOOR LOCK RECEIVER) GAUGES FUSE 4 GROUND DOOR JAMB SW LOCK SIG UNLOCK SIG PPL GRY WIRE HORNS SYSTEM HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (LEFT SIDE OF DASH, INTERIOR LAMPS SYSTEM LEFT DOOR LOCK SWITCH LEFT FRONT DOOR JAMB SWITCH LEFT FRONT DOOR LOCK ACTUATOR LEFT REAR DOOR JAMB SWITCH LEFT REAR DOOR LOCK ACTUATOR LOCK LT BLU WIRE ORG/ WIRE PNK WIRE PPL PWR-ACCY CIRCUIT BREAKER REAR CARGO DOOR LOCK ACTUATOR (CARGO DOORS) REAR DOOR JAMB SWITCH REAR DOOR LOCK SWITCH (CARGO DOORS) REMOTE CONTROL DOOR LOCK RECEIVER (BEHIND CENTER OF DASH) RIGHT DOOR LOCK SWITCH RIGHT FRONT DOOR JAMB SWITCH RIGHT FRONT DOOR LOCK ACTUATOR RIGHT REAR CARGO DOOR CONTACTOR (RIGHT REAR DOOR JAMB) RIGHT REAR DOOR JAMB SWITCH RIGHT REAR DOOR LOCK ACTUATOR RR DOOR SW BATT (B+) SEAT BELT SWITCH BREAKOUT) TAN WIRE TRUNK, TAIL- GATE, FUEL DOORS SYSTEM UNLOCK UTILITY W/ REAR CARGO DOORS UTILITY W/ REAR LIFT GATE/WINDOW W/ LIFTGATE W/ CARGO DOORS W/O POWER WINDOWS W/ POWER WINDOWS WHT WIRE

BATT B BELT SWITCH BREAKOUT) BLK WIRE BLK/WHT WIRE CIG LTR FUSE 13 CONVENIENCE CENTER (LEFT SIDE OF DASH) DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) DOOR LOCK RELAY (UNDER CENTER OF DASH, NEAR REMOTE CONTROL DOOR LOCK RECEIVER) DRIVER DR UNLK UNLOCK OUT HORN SIGNAL GAUGES FUSE 4 GROUND GRY WIRE HORNS SYSTEM HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (LEFT SIDE OF DASH, INTERIOR LAMPS SYSTEM LEFT DOOR LOCK SWITCH LEFT FRONT DOOR LOCK ACTUATOR LOCK LOCK OUT DOME LAMPS LT BLU WIRE ORG/ WIRE PASS DRS UNLK PNK IGNITION DOME LMP OFF PROGRAM SIG WIRE PNK WIRE PWR ACCY C.B. REMOTE CONTROL DOOR LOCK RECEIVER (UNDER CENTER OF DASH PANEL) RIGHT DOOR LOCK SWITCH RIGHT FRONT DOOR LOCK ACTUATOR SEAT BELT SWITCH BREAKOUT) TAN WIRE UNLOCK W/O POWER WINDOWS W/ POWER WINDOWS WHT WIRE