GM Service Manual Online
For 1990-2009 cars only

Important: For the inside rearview mirror with the automatic day-night feature or the rear window defogger, review the system operation in order to familiarize yourself with the system functions. Refer to the following:

Refer to Stationary Window Description .

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the rear window defogger and the automatic day-night feature of the inside rearview mirror.
    • Inspect the easily accessible system components for obvious damage or for conditions which could cause the symptom.

Intermittent

Bad electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Symptom List

Refer to a symptom diagnostic procedure from the following in order to diagnose the symptom:

Defogger Grid Lines Diagnosis .