Important: For the rear window defogger system, the following steps must be performed before using the symptom tables.
• There are no DTCs set. • The control modules can communicate via the serial data link. • Inspect for aftermarket devices which could affect the operation of the rear window defogger. Refer to
Rear Window Defogger Description and Operation. • Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections.
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom: