GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

  1. Turn the ignition switch to the OFF position.
  2. Place the interior lamps switch in the ON position.

All incandescent lighting on the INC DIM D2 output turns ON. INC DIM 2 includes all of the lighting on CKT 1244 (BRN), which is the backlighting for the headlamp switch and the floodlighting for the vehicle doors.

Incandescent Lamps Inoperative

2

  1. Place the interior lamps switch in the OFF position.
  2. Turn the ignition switch to the RUN position.
  1. INC DIM 2 lighting turns OFF.
  2. All of the VF displays light. VF displays include the following components (if equipped):
  3. • The radio (IRC)
    • The cellular telephone (PHN)
    • The Driver Information Center (DIC)
    • The instrument cluster (IPC)
    • The climate control panel (CCP)

3

  1. With the twilight off, cover the ambient light sensor.
  2. Place the headlamp switch in the PARK position.
  1. The park lamps turn ON.
  2. All of the VF displays dim in order to match the current dimming control level. All of the incandescent lighting for INC DIM 1 and INC DIM 2 light at the current dimming control level. INC DIM 1 includes all of the park lamp backlighting on CKT 8 (GRY) which is composed of the following components:
  3. • The radio (IRC)
    • The front cigar lighter
    • The steering wheel controls
    • The Driver Information Center (DIC)
    • The climate control panel (CCP)
    • The instrument cluster (IPC)
    • The heated seat switches
    • The auxiliary blower switches
    • The ash tray lamps
    • The PRNDL lamp

Exterior Lights System Check

4

Rotate the headlamp switch dimming control in both directions.

All of the VF displays and all of the incandescent lighting dim and brighten in response to the headlamp switch dimming control.

Vacuum Fluorescent Displays Do Not Dim with Instrument Panel Dimmer Switch

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.