GMC Pickup C2500 (1985-2000) service engine soon lamp Wiring diagrams

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/WHT WIRE DK BLU WIRE DK GRN WIRE EGR CONTROL PRESSURE/ BARO SENSOR (VIN P, S) (UPPER LEFT SIDE OF COWL) FUEL HEATER (TOP REAR OF ENGINE) FUEL PUMP IN-LINE FUSE 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 ECM-IGN FUSE HOT IN RUN, BULB TEST OR START HOT IN START OR RUN GLO PLUG FUSE IGNITION FEED 2-3 SHIFT SOL CTRL 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 SOL FUSE 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 (OR WHT) 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

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/WHT WIRE DK BLU WIRE DK GRN WIRE EGR CONTROL PRESSURE/ BARO SENSOR (VIN P, S) (UPPER LEFT SIDE OF COWL) FUEL HEATER (TOP REAR OF ENGINE) FUEL PUMP IN-LINE FUSE 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 ECM-IGN FUSE HOT IN RUN, BULB TEST OR START HOT IN START OR RUN GLO 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 SOL FUSE 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 (OR WHT) 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

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/WHT WIRE DK BLU WIRE DK GRN WIRE EGR CONTROL PRESSURE/ BARO SENSOR (VIN P, S) (UPPER LEFT SIDE OF COWL) FUEL HEATER (TOP REAR OF ENGINE) FUEL PUMP IN-LINE FUSE 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 ECM-IGN FUSE HOT IN RUN, BULB TEST OR START HOT IN START OR RUN GLO PLUG FUSE IGNITION FEED 2-3 SHIFT SOL CTRL 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 SOL FUSE 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 (OR WHT) 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/WHT WIRE DK BLU WIRE DK GRN WIRE EGR CONTROL PRESSURE/ BARO SENSOR (VIN P, S) (UPPER LEFT SIDE OF COWL) FUEL HEATER (TOP REAR OF ENGINE) FUEL PUMP IN-LINE FUSE 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 ECM-IGN FUSE HOT IN RUN, BULB TEST OR START HOT IN START OR RUN GLO 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 SOL FUSE 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 (OR WHT) 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

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/WHT WIRE DK BLU WIRE DK GRN WIRE EGR CONTROL PRESSURE/ BARO SENSOR (VIN P, S) (UPPER LEFT SIDE OF COWL) FUEL HEATER (TOP REAR OF ENGINE) FUEL PUMP IN-LINE FUSE 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 ECM-IGN FUSE HOT IN RUN, BULB TEST OR START HOT IN START OR RUN GLO PLUG FUSE IGNITION FEED 2-3 SHIFT SOL CTRL 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 SOL FUSE 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 (OR WHT) 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/WHT WIRE DK BLU WIRE DK GRN WIRE EGR CONTROL PRESSURE/ BARO SENSOR (VIN P, S) (UPPER LEFT SIDE OF COWL) FUEL HEATER (TOP REAR OF ENGINE) FUEL PUMP IN-LINE FUSE 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 ECM-IGN FUSE HOT IN RUN, BULB TEST OR START HOT IN START OR RUN GLO 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 SOL FUSE 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 (OR WHT) WIRE YEL WIRE YEL/BLK WIRE

A/C SIG AIR COND- ITIONING SYSTEM APP 3 SENS SIG FUEL TEMP SIG IAT SIG B/H BARO SENSOR (VIN F ONLY) (UPPER LEFT SIDE OF COWL) BLK WIRE BLK/WHT WIRE BLU WIRE BLU/WHT WIRE BRN/WHT WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE EGR CONTROL PRESSURE/ BARO SENSOR (VIN P, S) (UPPER LEFT SIDE OF COWL) FUEL HEATER (TOP REAR OF ENGINE) FUEL PUMP IN-LINE FUSE FUEL PUMP OIL PRESSURE SWITCH FUEL PUMP RELAY (RIGHT SIDE OF SAFETY WALL) 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 ECM-IGN FUSE HOT IN RUN, BULB TEST OR START HOT IN START OR RUN GLO PLUG FUSE IGNITION FEED INSTRUMENT CLUSTER INSTRUMENT CLUSTERS SYSTEM LEFT BANK GLOW PLUGS LT BLU/BLK WIRE LT GRN WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (VIN F, S) (LEFT REAR ENGINE COMPT, AT COWL) ORG/ WIRE ORG/BLK WIRE PNK 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 SOL FUSE TAN WIRE TAN/BLK WIRE TCC/ BRAKE SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) WAIT LAMP "SERVICE THROTTLE" LAMP WASTEGATE SOL CTRL EGR VENT SOL CTRL "SERVICE THROTTLE" LAMP WHT WIRE WHT/BLK WIRE YEL (OR WHT) WIRE YEL WIRE YEL/BLK WIRE