GMC Rally G2500 (1985-1995) wht Wiring diagrams

2-DR CAB 2-DR CAB AUXILIARY LEAD (TAPED TO BODY, NEAR FUSE BLOCK) DK BACKUP LIGHT SWITCH (ON STEERING COLUMN) BLK WIRE BLU WIRE BRN WIRE CENTER HIGH MOUNT STOP LAMP CHMSL GROUND (NEAR CHMSL) DK BLU WIRE DK GRN WIRE FUSE FUSE BLOCK (LEFT SIDE OF I/P) GRN WIRE HAZARD HAZARD FLASHER HEAD OFF PARK HEADLIGHT SWITCH HOT AT ALL TIMES HOT IN RUN OR START IN-LINE FUSE INSTRUMENT CLUSTER JUNCTION BLOCK (LEFT SIDE OF COWL) LEFT BACKUP LIGHT LEFT FRONT MARKER LIGHT LEFT FRONT PARK/ TURN LIGHTS LEFT REAR MARKER LIGHT RIGHT REAR MARKER LIGHT RH LH LEFT TAIL/ STOP/ TURN LIGHT LEFT TURN IND LEFT TURN, HAZARD LICENSE LIGHTS LT BLU WIRE LT GRN WIRE NORMAL NOTE:BULBS ARE CASE GROUNDED W/ 2-DR CAB ORG/ WIRE PPL RED WIRE RIGHT BACKUP LIGHT RIGHT FRONT MARKER LIGHT RIGHT FRONT PARK/ TURN LIGHTS RIGHT TAIL/ STOP/ TURN LIGHT RIGHT TURN IND RIGHT TURN, HAZARD STOP -HZ STOP LAMP SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) TAIL LPS TURN B/U TURN FLASHER TURN/ HAZARD SWITCH W/ DRL W/O DRL W/OPTIONAL HEAVY-DUTY TRAILER TOW PACKAGE W/OPTIONAL TRAILER TOW PACKAGES WARNINGS SYSTEM WHT WIRE WIRE LEADS ARE SPLICED TO TRAILER WIRING, OR CONNECTED TO TRAILER WIRE PLUG YEL WIRE

2-DR CAB AUXILIARY LEAD (TAPED TO BODY, NEAR FUSE BLOCK) DK BACKUP LIGHT SWITCH (ON STEERING COLUMN) BLK WIRE BLU WIRE BRN WIRE CENTER HIGH MOUNT STOP LAMP CHMSL GROUND (NEAR CHMSL) DK BLU WIRE DK GRN WIRE FUSE FUSE BLOCK (LEFT SIDE OF I/P) GRN WIRE HAZARD HAZARD FLASHER HEAD OFF PARK HEADLIGHT SWITCH HOT AT ALL TIMES HOT IN RUN OR START IN-LINE FUSE INSTRUMENT CLUSTER JUNCTION BLOCK (LEFT SIDE OF COWL) LEFT BACKUP LIGHT LEFT FRONT MARKER LIGHT LEFT FRONT PARK LIGHT RIGHT FRONT PARK LIGHT LEFT FRONT PARK/ TURN LIGHT LEFT TAIL/ STOP/ TURN LIGHT LEFT REAR MARKER LIGHT LEFT TURN IND LEFT TURN, HAZARD LICENSE LIGHTS LT BLU WIRE LT GRN WIRE NORMAL NOTE:BULBS ARE CASE GROUNDED W/ 2-DR CAB ORG/ WIRE PPL RED WIRE RIGHT BACKUP LIGHT RIGHT FRONT MARKER LIGHT RIGHT FRONT PARK/ TURN LIGHT RIGHT REAR MARKER LIGHT RH LH RIGHT TAIL/ STOP/ TURN LIGHT RIGHT TURN IND RIGHT TURN, HAZARD STD 2-DR CAB STOP -HZ STOP LAMP SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) TAIL LPS TURN B/U TURN FLASHER TURN/ HAZARD SWITCH W/OPTIONAL HEAVY-DUTY TRAILER TOW PACKAGE W/OPTIONAL TRAILER TOW PACKAGES WARNINGS SYSTEM WHT WIRE WIRE LEADS ARE SPLICED TO TRAILER WIRING, OR CONNECTED TO TRAILER WIRE PLUG YEL WIRE

1995 VFTC ANTI-LOCK BRAKE PUMP MOTOR AUDIO ALARM MODULE BLK WIRE BLK/WHT WIRE BODY BUILDER FRONT MARKER LAMP BODY BUILDER REAR MARKER LAMP BRAKE/ TRANSMISSION SHIFT INTERLOCK SOLENOID SAFETY BELT RETRACTOR SWITCH CIGARETTE LIGHTER COOLANT LEVEL INDICATOR CRUISE CONTROL SERVO DATA LINK CONNECTOR DAYTIME RUNNING LAMPS MODULE DAYTIME RUNNING LAMPS RELAY ENGINE COOLANT LEVEL INDICATOR MODULE FLOW SWITCH (BRAKES) FUEL HEATER GLOW PLUG LAMP INDICATOR GLOW PLUG MODULE HD TRAILER TOW PACKAGE REAR A/C BLOWER MOTOR HEATER CONTROL LAMP INSTRUMENT CLUSTER LEFT BACKUP LAMP LEFT GRID DEFOGGER LEFT REAR SIDE MARKER LAMP LEFT SIDE MARKER LAMP LEFT TAIL/ STOP AND TURN LAMP SIGNAL LIGHT SWITCH MODULE NCA WIRE POWERTRAIN CONTROL MODULE (PCM) RADIO RIGHT BACKUP LAMP RIGHT GRID DEFOGGER RIGHT REAR SIDE MARKER LAMP RIGHT SIDE MARKER LAMP RIGHT TAIL/ STOP AND TURN LAMP SIGNAL TAN/WHT WIRE VEHICLE SPEED SENSOR BUFFER W/ DIESEL ENGINES WATER IN-FUEL SENSOR WHT WIRE WINDSHIELD WASHER PUMP WINDSHIELD WIPER MOTOR MODULE

BLK WIRE BRN WIRE DAYTIME RUNNING LAMP INDICATOR DAYTIME RUNNING LAMPS MODULE (IN I/P HARNESS) DAYTIME RUNNING LAMPS RELAY (IN I/P HARNESS) DK BLU/WHT WIRE DK GRN/YEL WIRE FUSE BLOCK GRN WIRE HEAD PARK HEADLAMP DIMMER SWITCH HEADLIGHT SWITCH ASSEMBLY HI BEAM INDICATOR HI LO HORN/DM FUSE HOT AT ALL TIMES HOT IN RUN HTR FUSE INSTRUMENT CLUSTER LEFT HEADLAMP ASSEMBLY LT GRN WIRE LT GRN/BLK WIRE OFF OFF HEAD ORG/ WIRE PARK PARK BRAKE WARNING SWITCH (AT PARK BRAKE, UNDER LEFT SIDE OF I/P) PROVISIONS FOR FOG LAMPS RIGHT HEADLAMP ASSEMBLY TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE

"TRANS" LAMP 1-2 SHIFT SOL 2-3 SHIFT SOL TCC SOL 2-3 SHIFT SOL CTRL 1-2 SHIFT SOL CTRL DIAGNOSTIC TEST A/C INPUT BRAKE SIGNAL TCC CONTROL PPL AIR CONDI- TIONING SYSTEM AIR CONDITIONING SYSTEM B/H BATTERY FEED BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRAKE/TRANS- MISSION SHIFT INTERLOCK RELAY (ON STEERING COLUMN) BRN WIRE DATA LINK CONNECTOR (UNDER LEFT SIDE OF I/P) DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE ECM BAT FUSE ELECTRONIC 4-SPEED AUTOMATIC OVERDRIVE TRANSMISSION ENGINE SPEED SENSOR (TOP REAR OF ENGINE) ENGINE SPEED SIGNAL SENSOR GROUND TP SENSOR INPUT FUSE BLOCK FUSIBLE LINK (20 GA- RUST) FUSIBLE LINK FUSIBLE LINKS GAGES FUSE GLOW PLUG CONTROLLER (LEFT SIDE OF ENGINE) GLOW PLUG WAIT LAMP GRN WIRE GRY WIRE GRY/BLK WIRE GRY/RED WIRE HOT AT ALL TIMES HOT AT ALL TIMES FUSIBLE LINK HOT IN CRANK HOT IN RUN, BULB TEST OR START HOT IN START OR RUN IGNITION SWITCH INPUTS INSTRUMENT CLUSTER (LEFT SIDE OF I/P) LEFT BANK GLOW PLUGS LT BLU/WHT WIRE LT GRN WIRE LT PPL ORG/ WIRE ORG/BLK WIRE PCS HI PCS LO IGNITION PNK RANGE SIGNAL A RANGE SIGNAL B RANGE SIGNAL C WIRE PNK WIRE PNK/BLK WIRE PPL PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE RIGHT BANK GLOW PLUGS SERVICE TRANS OUTPUT SERIAL DATA STARTER MOTOR (LOWER RIGHT REAR OF ENGINE) SYSTEM GROUND SYSTEM GROUND 452 416 SENSOR GROUND 5 VOLTS REF TAN WIRE TCC/BRAKE SWITCH (ON BRAKE PEDAL SUPPORT) TRAN- SMISSION FLUID TEMP (TFT) SENSOR TRANS FLUID TEMP SIG MAP SENS TRANS FUSE ECM I FUSE TRANSMISSION CONTROL MODULE (TCM) (BELOW DRIVER SEAT) TRANSMISSION INPUT SPEED SENSOR (LEFT FRONT SIDE OF TRANSMISSION) VEHICLE SPEED INPUT TRANS INPUT SPD LO TRANS INPUT SPD HI VEHICLE SPEED SENSOR (REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT SIDE OF I/P) VEHICLE SPD OUTPUT VSS WHT WIRE WHT/BLK WIRE YEL/BLK WIRE

"TRANS" LAMP 1-2 SHIFT SOL 2-3 SHIFT SOL TCC SOL 2-3 SHIFT SOL CTRL 1-2 SHIFT SOL CTRL DIAGNOSTIC TEST A/C INPUT BRAKE SIGNAL TCC CONTROL PPL ACCY AIR CONDI- TIONING SYSTEM ALT FUSE B/H BATTERY FEED BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BLU WIRE BRN WIRE BULB TEST COLD ADVANCE FAST IDLE TEMPERATURE SWITCH (RIGHT REAR OF ENGINE) COLD ADVANCE SOLENOID (TOP FRONT OF ENGINE) DATA LINK CONNECTOR (BEHIND LEFT SIDE SHIPPING DIODE (BEHIND GENERATOR) DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE ECM BAT FUSE ECM CRANK FUSE ELECTRONIC 4-SPEED AUTOMATIC OVERDRIVE TRANSMISSION ENGINE SPEED SIGNAL SENSOR GROUND TP SENSOR INPUT FAST IDLE SOLENOID (TOP LEFT SIDE OF ENGINE) FUEL HEATER (TOP REAR OF ENGINE) FUEL SHUT- OFF SOLENOID (TOP FRONT OF ENGINE) FUSE BLOCK FUSIBLE LINK (20 GA-RUST) FUSIBLE LINKS GLOW PLUG CONTROLLER (LEFT SIDE OF ENGINE) GLOW PLUG WAIT LAMP GRY WIRE GRY/BLK WIRE GRY/RED WIRE HOT AT ALL TIMES HOT AT ALL TIMES FUSIBLE LINK HOT IN CRANK HOT IN RUN, BULB TEST OR START INPUTS INSTRUMENT CLUSTER LEFT BANK GLOW PLUGS LOCK OFF LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE ORG/ WIRE ORG/BLK WIRE PANEL) PCS HI PCS LO IGNITION PNK RANGE SIGNAL A RANGE SIGNAL B RANGE SIGNAL C WIRE PNK WIRE PNK/BLK WIRE PPL PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE RIGHT BANK GLOW PLUGS RUN WIRE SERVICE TRANS OUTPUT SERIAL DATA SYSTEM GROUND SYSTEM GROUND 452 416 SENSOR GROUND 5 VOLTS REF TAN/BLK WIRE TCC/BRAKE SWITCH (ON BRAKE PEDAL SUPPORT) TRANS FLUID TEMP SIG MAP SENS TRANS FUSE TRANS- MISSION FLUID TEMP (TFT) SENSOR TRANSMISSION CONTROL MODULE (TCM) (BEHIND LEFT SIDE OF SHIPPING PANEL) TRANSMISSION INPUT SPEED SENSOR (LEFT SIDE OF TRANSMISSION) VEHICLE SPEED INPUT TRANS INPUT SPD LO TRANS INPUT SPD HI VEHICLE SPEED SENSOR (REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT SIDE OF I/P) VEHICLE SPD OUTPUT VSS WATER IN FUEL INDICATOR WATER-IN FUEL SENSOR (TOP REAR OF ENGINE) WHT WIRE WHT/BLK WIRE YEL/BLK WIRE

4.3L 5.7L 5.7L ONLY 4.3L ONLY 7.4L 7.4L ONLY AIR CONDITION- ING SYSTEM BLK WIRE BLK/RED WIRE BLK/WHT WIRE BLK/YEL WIRE BRN WIRE BRN/WHT WIRE CRUISE CONTROL SYSTEM CRUISE SIGNAL DIAGNOSTIC TEST TP SENSOR SIGNAL INJECTOR 1 CONTROL DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE DK GRN/YEL WIRE ECM BAT FUSE ECM CRNK FUSE EGR CONTROL GOVERNOR CONTROL EGR ELECTONIC VACUUM REGULATOR SOLENIOD VALVE (TOP RIGHT FRONT OF ENGINE) EVAPORATIVE CANISTER PURGE CONTROL SOLENOID (TOP RIGHT SIDE OF ENGINE) EXHAUST GAS RECIRCULATION VALVE SOLENOID (TOP RIGHT SIDE OF ENGINE) FUEL PUMP RELAY CTRL PCS LOW FUEL PUMP SIGNAL MAP SIGNAL FUSE BLOCK GRY WIRE GRY/RED WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START IC BYPASS SENSOR GROUND SENSOR GROUND TFT SIGNAL IDLE AIR CONTROL ACTUATOR (TOP REAR OF ENGINE) IDLE SPEED ACTUATOR CONTROL SOLENOID (NO LOCATION AVAILABLE) INJ FUSE KNOCK SENSOR INPUT ECT SIGNAL KNOCK SIGNAL EGR PINTLE POSITION SIGNAL LINEAR EGR VACUUM REGULATOR SOLENOID VALVE (TOP FRONT OF ENGINE) LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE ORG/ WIRE OXYGEN SENSOR GROUND PNK 26 27 WIRE PNK WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF SHIPPING PANEL) PPL PPL 24 25 PPL/WHT WIRE RANGE SIGNAL A INPUT SPEED SIGNAL HIGH INPUT SPEED SIGNAL LOW RANGE SIGNAL B RANGE SIGNAL C MIL CONTROL RED WIRE RED/BLK WIRE TAN WIRE TAN/BLK WIRE THROTTLE BODY FUEL INJECTOR #1 (TOP OF THROTTLE BODY UNIT) THROTTLE BODY FUEL INJECTOR #2 (TOP OF THROTTLE BODY UNIT) TRANSMISSION INPUT SPEED SENSOR (NO LOCATION) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

3 121 PNK WIRE 4.3L AND 7.4L 5.7L ACCY ALT FUSE BLK WIRE BLK/RED WIRE BLK/YEL WIRE BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (TOP FRONT OF ENGINE) FUSE BLOCK GRY WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START IGNITION COIL (TOP RIGHT REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (LEFT REAR OF ENGINE, NEAR OIL PRESSURE SENDER) KNOCK SENSOR MODULE (TOP RIGHT SIDE OF ENGINE) LOCK OFF LT BLU/WHT WIRE LT GRN WIRE MALFUNCTION (SERVICE ENGINE SOON) INDICATOR MANIFOLD ABSOLUTE PRESSURE SENSOR (ABOVE VALVE COVER) NCA WIRE ORG/ WIRE PNK 25 26 WIRE PNK WIRE PNK/BLK WIRE PPL PPL 2 3 4 PPL 23 24 PPL/WHT WIRE PROVISIONS FOR TACHOMETER RED WIRE RED/BLK WIRE RUN WIRE TAN/BLK WIRE TCC/BRAKE SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) THROTTLE POSITION SENSOR (ON THROTTLE BODY) TRANS FUSE WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

5.7L 7.4L 7.4L ONLY AIR CONDITION- ING SYSTEM BLK WIRE BLK/RED WIRE BLK/WHT WIRE BLK/YEL WIRE BRN WIRE BRN/WHT WIRE DIAGNOSTIC TEST TP SENSOR SIGNAL INJECTOR 1 CONTROL DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE DK GRN/YEL WIRE ECM BAT FUSE ECM I FUSE ECT SIGNAL EGR CONTROL EVAPORATIVE CANISTER PURGE CONTROL SOLENOID (TOP RIGHT SIDE OF ENGINE) EXHAUST GAS RECIRCULATION VALVE SOLENOID (TOP RIGHT SIDE OF ENGINE) FUEL PUMP RELAY CTRL PCS LOW FUEL PUMP SIGNAL MAP SIGNAL FUSE BLOCK GRY WIRE GRY/RED WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START IC BYPASS SENSOR GROUND SENSOR GROUND TFT SIGNAL 470 455 PPL IDLE AIR CONTROL ACTUATOR (TOP REAR OF ENGINE) IDLE SPEED ACTUATOR CONTROL SOLENOID (NO LOCATION AVAILABLE) KNOCK SIGNAL EGR PINTLE POSITION SIGNAL LINEAR EGR VACUUM REGULATOR SOLENOID VALVE (TOP FRONT OF ENGINE) LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE NCA WIRE ORG/ WIRE OXYGEN SENSOR (IN EXHAUST MANIFOLD) OXYGEN SENSOR GROUND PNK 22 23 WIRE PNK RANGE SIGNAL A INPUT SPEED SIGNAL HIGH INPUT SPEED SIGNAL LOW WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF SHIPPING PANEL) PPL PPL 20 21 PPL/WHT WIRE RANGE SIGNAL B RANGE SIGNAL C MIL CONTROL RED 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) TRANSMISSION INPUT SPEED SENSOR (LEFT SIDE OF TRANSMISSION) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

3 121 PNK WIRE ACCY BLK WIRE BLK/RED WIRE BLK/YEL WIRE BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (TOP FRONT OF ENGINE) FUSE BLOCK GAGES FUSE GRY WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START IGNITION COIL (TOP RIGHT REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (LEFT REAR OF ENGINE, NEAR OIL PRESSURE SENDER) LOCK OFF LT BLU/WHT WIRE LT GRN WIRE MALFUNCTION (SERVICE ENGINE SOON) INDICATOR MANIFOLD ABSOLUTE PRESSURE SENSOR (ABOVE VALVE COVER) NCA WIRE ORG/ WIRE PNK 22 23 WIRE PNK WIRE PNK/BLK WIRE PPL PPL 20 21 PPL 3 4 PPL/WHT WIRE PROVISIONS FOR TACHOMETER RED WIRE RED/BLK WIRE RUN WIRE TAN/BLK WIRE TCC/BRAKE SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) THROTTLE POSITION SENSOR (ON THROTTLE BODY) TRANS FUSE WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE