GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

  1. Apply the parking break.
  2. Expose the photoresistor to a bright incandescent lamp.
  3. Move the gear selector to PARK.
  4. Start the engine and allow the engine to idle.
    • The low beam headlamps are off.
    • The high beam headlamps are off.

2

  1. Release the parking brake.
  2. Cover the photoresistor in order to block light intrusion.
  3. Keep the gear selector in PARK.

The headlamps and the park lamps illuminate after a short delay.

3

  1. Expose the photoresistor to a bright incandescent lamp.
  2. Move the transaxle out of PARK with the engine running.

The high beam headlamps come ON at a reduced intensity (DRL mode).

4

  1. Move the headlamp dimmer switch to LOW.
  2. Turn the headlamp switch to HEAD.
    • The low beam headlamps are on.
    • The high beam headlamps are off.

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