GM Service Manual Online
For 1990-2009 cars only

Headlamps

The headlamps consist of 2 interchangeable single filament bulbs that provide high and low beams. The inner bulb in the headlamp is the high beam.The outer bulb is the low beam.

Headlamp Switch

The headlamp switch is located to the left of the instrument cluster. The headlamp switch includes controls for the following components:

    • The park lamps
    • The headlamps
    • The twilight sentinel
    • The interior dimming
    • The courtesy lamps
    • The Lights On indicator

Ambient Light Sensor

The ambient light sensor is located in the center of the defroster grille. The ambient light sensor is a current generator that changes as the light level through the windshield changes. Daylight or nighttime conditions are determined by the value of the ambient light sensor. If an object is covering the ambient light sensor, the vehicle may act as if nighttime conditions exist even though it is daytime.

Front Park/Side Marker/Cornering Lamps

The front park, side marker, and optional cornering lamp are all an integral part of the headlamp assembly. The side marker lamp is amber in color and contains reflectors in order to alert approaching vehicles for nighttime driving safety. The optional cornering lamp is clear and lights the peripheral turn area of the vehicle when the appropriate turn signal is in use.

Turn Signal Lamp

The front turn signal lamps are amber in color and are mounted in the front corner of the front bumper fascia.

Tail Lamps

The tail, stop, and turn signal functions are performed by the quarter mounted tail lamps and rear compartment lid assembly tail lamps. The quarter mounted tail lamp consists of a red lens, a turn/stop lamp bulb, and a tail lamp. The quarter mounted tail lamp wraps around the corner of the vehicle and provides the rear side marker. The lower portion of the lamp contains reflectors in order to alert approaching vehicles for driving nighttime safety. The rear compartment lid lamp assembly consists of 4 tail lamp bulbs, 2 backup lamp bulbs, and 2 license lamp bulbs.

Center High Mounted Stoplamp (CHMSL)

The center high mounted stoplamp (CHMSL) is located on the center of the rear package self. The CHMSL operates simultaneously with the rear stoplamps and provides increased visibility of vehicle braking.

License Lamps

The license lamps consist of 2 clear bulbs. The bulbs are located in the rear compartment lid lamp assembly. The license lamps illuminate the license plate of the vehicle when the park lamps are on.

Hazard Lamps

The hazard switch is located in the top of the steering column to the right of the turn signal multifunction lever. The hazard function uses all of the left and the right turn lamps.

Stoplamp/Auto Trans Shift Lock Control Switch

The stoplamp/auto trans shift lock control switch is located under the instrument panel, near the top of the brake pedal.

Backup Lamps

The backup lamps are white, located in the rear compartment lid lamp assembly. The backup lamps provide rear lighting and alert others when the vehicle is in reverse.

Underhood Lamp

The underhood lamp is located in the engine compartment, on the left rear of the hood.

Reading Lamps

On vehicles with the DH6 option there are 2 reading lamps located in the overhead console and 1 located in the headliner above each rear door. Each reading lamp has a switch that is used in order to turn the reading lamp on and off.

Courtesy Lamps

Courtesy lamps are located in the driver foot well and passenger foot well. On vehicles with the C90 option there is also a courtesy lamp located in each door. The reading lamps are also used as courtesy lamps. Courtesy lamps are used in order to illuminate the vehicle during nighttime conditions. The lamps may also be manually turned on or off using the courtesy lamp switch which is integral with the IP dimmer control. This switch is activated when the dimmer control is raised to a full up location.

IP Dimmer Control

The IP Dimmer control is located on the headlamp switch assembly. The IP dimmer control is used in order to adjust the instrument panel back lighting and VF display intensity.

Rear Compartment Lamp

The rear compartment lamp is located in front center of the rear compartment.

Vanity Lamps

The vanity lamps are located in the center of each sunshade.

IP Compartment Lamp

The IP compartment lamp is located in IP compartment, on the right side of the instrument panel.

Interior Lamps Dimming

The instrument cluster (IPC), radio, and heater and A/C control assembly all have vacuum fluorescent (VF) displays, if equipped. The incandescent lamps include the following components:

    • The ashtray lamp
    • The headlamp dimmer switch
    • The heated seat switches, if equipped
    • The steering wheel controls
    • Two driver information center (DIC) switches
    • The release switch assembly
    • The headlamp switch
    • The radio
    • The heater and A/C control assembly
    • The passenger side heater and A/C control assembly, if equipped
    • The heads up display (HUD) switch
    • Four power window switches
    • Four power door lock switches
    • The memory function switch, if equipped

The incandescent lamps and VF displays may be dimmed in order to change the amount of light inside the vehicle.