GM Service Manual Online
For 1990-2009 cars only

Important: The following steps must be completed before using the symptom table.

    • Perform the Diagnostic System Check - Vehicle before using a symptom table in order to verify that all of the following conditions are true:
       - There are no DTCs set.
       - The control modules can communicate via the serial data link.
    • Review the system description and operation in order to familiarize yourself with the system functions. Refer to the following:
       -  Interior Lighting Systems Description and Operation.
       -  Exterior Lighting Systems Description and Operation.

Visual/Physical Inspection

    • Inspect for aftermarket devices which may affect the operation of the lighting system. Refer to Checking Aftermarket Accessories.
    • Inspect the easily accessible or visible system components for obvious damage or conditions which may cause the symptom.

Intermittent

Thoroughly inspect the wiring and connectors. An incomplete inspection of the wiring and connectors may result in misdiagnosis causing part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections.

Symptom List

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

    •  Backup Lamps Malfunction
    •  Courtesy Lamps Malfunction
    •  Daytime Running Lamps Malfunction
    •  Front Fog Lamps Malfunction
    •  Hazard Lamps Malfunction
    •  Headlamps Malfunction
    •  Interior Backlighting Malfunction
    •  Park, License, and/or Tail Lamps Malfunction
    •  Stop Lamps Malfunction
    •  Trailer Lamps Malfunction
    •  Turn Signal Lamps and/or Indicators Malfunction