GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

  1. Turn the ignition switch on.
  2. Cover the ambient light sensor (windshield side) with a dark cloth and shine a light on the headlamp sensor (mirror side).
  3. Step firmly on the brake pedal.
  4. Shift the transaxle gear selector lever in the REVERSE position.
  1. The mirror gradually darkens.
  2. The mirror gradually lightens to a clear state.

Automatic Day-Night Mirrors Inoperative

2

  1. Shift the transaxle gear selector lever in the PARK position.
  2. Remove the cloth and light.
  1. The mirror gradually darkens.
  2. The mirror lightens to a clear state.

Mirrors - Automatic Day-Night Inoperative in Reverse

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