GM Service Manual Online
For 1990-2009 cars only

Front Park Lamps

Whenever the park lamps are ON, voltage is applied from the Fuse H5-H6 through circuit 9 to the underhood accessory wiring junction block. The voltage is then applied to the front park lamps.

Tail and License Plate Lamps

Voltage is applied at all times from Fuse 30 to the headlamp switch through circuit 1340. When the headlamp switch is turned to the PARK or HEAD position, voltage is applied to circuit 74. Voltage is then applied to through circuit 74 to the Fuse H7-H8, From the fuse voltage is applied to circuit 301. Voltage then is applied to the tail and license plate lamps, turning the lamps ON.

Turn Signal Lamps

Voltage is applied from the Fuse D1-D2 to the normally closed pole of the hazard switch in the turn signal switch when the ignition is in the RUN, BULB TEST or the START position. The voltage then flows through circuit 539, which feeds the hazard lamp/turn signal lamp flasher through circuit 1508. With the turn signal switch in the turn position, voltage is applied through 3 circuits:

    • 57/58 for the cornering lamps.
    • circuit 14 for the front turn signal lamps and side repeater lamps.
    • circuit 18/19 for the rear turn lamps.

Cornering Lamps

When the turn signal switch is placed in the TURN LEFT position, voltage is applied through the closed contacts of the turn signal switch, to the LH cornering lamps through circuit 57. The LH cornering lamps are grounded through circuit 1350 to G101. When the turn signal switch is placed in the TURN RIGHT position, voltage is applied through the closed contacts of the turn signal switch, to the RH cornering lamps through circuit 58. The RH cornering lamps are grounded through circuit 1250 to G102.

Hazard Lamps

Voltage is applied at all times from the Fuse F3-F4 to the normally open poles of the hazard switch in the turn signal switch through circuit 1840. The hazard lamp/turn signal lamp flasher receives voltage through circuit 1508 when the hazard switch is in the HAZARD position. The current flow heats the timing element in the hazard lamp/turn signal lamp flasher. The voltage continuously opens and closes circuit 16 to the turn signal switch and then to all the turn signal lamps and both of the turn telltale lamps. All of the turn signal lamps and both of the turn telltale lamps flash ON and OFF.

Stop Lamps

Voltage is applied at all times from the Fuse F5-F6 to the stop lamp switch through circuit 140. Voltage is applied from the stop lamp switch to the turn signal switch through circuit 17 when the brake pedal is depressed. The voltage turns on the left and the right tail/stop lamps and the center high mounted stop lamp (CHMSL) The ground circuit is supplied through circuit 250 from G401 for the LH stop lamp and circuit 350 from G402 for the RH stop lamp and CHMSL.

Front Turn Signal and Side Repeater Lamps

Voltage is applied through the turn signal switch to circuit 14 for the LH side and circuit 15 for the RH side, through the underhood accessory wiring junction block to the side repeater and turn signal lamps. The ground for the side repeater lamps and the turn signal lamps is applied from circuit 1350 from G101.

Rear Turn Lamps

Voltage is applied through the turn signal switch circuit 18 for the LR and circuit 19 for the RR to the rear turn lamps. The ground is applied through circuit 250 from G401 for the LR turn lamps and circuit 350 from G402 for the RR turn lamps.