GM Service Manual Online
For 1990-2009 cars only

Interior Lamps

The interior lighting system includes the following components:

    • The instrument panel lamp dimmer
    • The ashtray illumination lamp
    • The cigar lighter illumination lamp
    • The dome lamp
    • The map lamp
    • The rear compartment lamp

IP Lamp Dimmer

Voltage is supplied to the IP lamp dimmer and the illumination lamps when the light switch is in the PARK or HEAD position. The solid state dimmer controls the amount of ground provided to the lamps. The solid state dimmer is grounded to G204 through junction block 3. All of the interior displays are grounded through the 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, Gages, and Console for IP lamp dimmer removal and installation procedures.

Ashtray Illumination Lamp

The ashtray illumination lamp lights whenever the parking lamps or the headlamps are activated.

Cigar Lighter Illumination Lamp

The cigar lighter illumination lamp lights whenever the parking lamps or headlamps are activated. The cigar lighter illumination lamp bulb socket is attached to the cigar lighter. Refer to Cigar Lighter Housing Replacement in Instrument Panel, Gages, and Console for cigar lighter removal and installation procedures.

Dome Lamp

The dome lamp is located in the center of the headliner. The dome lamp consists of a clear lens, the dome lamp bulb and a three position slide switch. The slide switch has the following three detent positions:

    • OFF
    • DOOR
    • ON

Power comes from the dome fuse, through junction block 1, and finally to the dome lamp. When the switch is in the OFF position, the dome lamp will not light. When the dome lamp switch is in the DOOR position, the lamp will light when any door is open (the door jamb switch is closed). The lamp will remain on until all of the doors are closed. When the dome lamp switch is placed in the ON position, it provides a path to ground to the dome lamp and the lamp will illuminate.

Door Activated Courtesy Lighting

Power comes from the dome fuse, through junction block 1 and finally to the dome lamp. When any door is opened, the corresponding door jamb switch contacts close. The closed contacts causes the multifunction alarm module to provide ground to the dome lamp and the lamp will illuminate.

Keyless Entry Interior Illumination

Power comes from the dome fuse, through junction block 1 and finally to the dome lamp. When the transmitter activates the keyless entry system it causes the multifunction alarm module to provide ground to the dome lamp, and the lamp will illuminate.

Map Lamp

On vehicles equipped with a power sunroof, a map lamp is incorporated into the power sunroof switch. The map lamp consists of the following components:

    • The map lamp bulb
    • A clear lens
    • A two-position push switch

Power comes from the dome fuse, through junction block 1 and then finally to the Courtesy/Reading lamp. When the light switch is depressed to the ON position, it provides power to the courtesy/reading lamp. Current flows through the lamp and then continues to ground (G200). Pushing the switch a second time turns the map lamp off.

Rear Compartment Lamp

Power comes from the dome fuse, through junction block 1 and finally to the rear compartment lamp. When the rear compartment lid is opened the rear compartment lamp switch closes providing a path to ground (chassis ground). With ground and power supplied the lamp will illuminate.