GM Service Manual Online
For 1990-2009 cars only

Headlamps

The turn signal/headlamp switch lever is located on the left side of the steering column. A twist-type knob on the end of the turn signal/headlamp switch lever controls the operation of the parking lamps and headlamps. When either the parking lamps or headlamps are activated, the tail lamps and rear license plate lamps illuminate also. When either the parking lamps or headlamps are activated, the instrument cluster assembly, cigar lighter, IP ashtray and the manual selector lever illumination lamps illuminate. The instrument panel and instrument cluster assembly illumination lamps intensity is controlled by the IP lamp dimmer, instead of remaining at 100 percent. The turn signal/headlamp switch lever controls the operation of both low beam and high beam headlamps. With the headlamps activated, pushing the lever toward the instrument panel into the detent position changes the headlamps from low beam to high beam operation. Pulling the lever toward the driver to the center position will return the headlamps from high beam operation to low beam operation.

The Flash-to-Pass feature allows the driver to signal the driver of another vehicle his intention to pass. This is achieved by pushing the lever toward the instrument panel, which will cause the high beam operation to illuminate until the lever is released.

Refer to Turn Signal Switch Replacement - On Vehicle in Steering Wheel and Column - Standard or Steering Wheel and Column - Tilt or Headlamp Switch Replacement for turn signal/headlamp switch removal and installation procedures.

Hazard Lamps

The hazard switch is located above the heater control assembly and controls the operation of the hazard lamp circuit. Pressing the hazard switch to the ON position will cause the turn/hazard signal relay to disengage the turn signal circuit and engage the hazard lamp circuit. This causes both turn indicators in the instrument cluster assembly to flash on and off along with all exterior turn signal lamps. The hazard lamp circuit will operate regardless of the position of the ignition switch. Press the hazard switch a second time in order to turn the hazard lamps off. Turning the hazard switch off disengages the hazard lamp circuit and returns the turn/hazard signal relay to the turn signal mode.

Refer to Hazard Flasher Switch Replacement in Instrument Panel, Gauges and Console for hazard switch removal and installation procedures.

IP Lamp Dimmer

The intensity of the instrument panel and instrument cluster assembly lamps is controlled by the IP lamp dimmer located on the left side of the instrument panel. The parking lamps or headlamps must be activated for the instrument panel and instrument cluster assembly lamps to be illuminated. When the parking lamps or headlamps are activated, rotating the IP lamp dimmer counterclockwise will decrease the instrument cluster assembly, rear window defogger switch, heater control assembly, ashtray and cigar lighter lamps illumination. Illumination of the radio display will revert from 100 percent to the setting of the IP lamp dimmer.

Refer to Instrument Panel Lamp Dimmer Switch Replacement in Instrument Panel, Gauges and Console for IP lamp dimmer removal and installation procedures.

Turn Signal

The turn signal/headlamp switch lever is located on the left side of the steering column. Turn signal operation is controlled by the turn/hazard signal relay located in Junction Block #1 and the turn signal/headlamp switch lever. For the turn signals to operate, the ignition switch must be in the ON position.

When making a partial turn, such as when changing lanes, the driver has the option of moving the lever to a detent stop. The turn signal lamps and the turn signal indicator will continue to flash as long as the lever is held in this position and will cancel automatically when the lever is released. The detent position allows a lane change or shallow turn to be made without failing to cancel the turn signal lamp. Moving the lever past the detent position to its furthest upward or downward position will provide conventional turn signal operation.