GM Service Manual Online
For 1990-2009 cars only

Important: The following steps must be completed before using a 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:
       -  Exterior Lighting Systems Description and Operation
       -  Interior Lighting Systems Description and Operation

Visual/Physical Inspection

    • Inspect for aftermarket devices which could 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 could 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 Always On
    •  Backup Lamps Inoperative
    •  Daytime Running Lamps (DRL) Inoperative
    •  Fog Lamp Indicator Inoperative
    •  Fog Lamps Always On
    •  Fog Lamps Inoperative
    •  Hazard Lamps Always On
    •  Hazard Lamps Inoperative
    •  Headlamp Low or High Beams Always On
    •  Headlamps Inoperative - High Beams
    •  Headlamps Inoperative - Low Beams
    •  Low and High Beams Headlamps Inoperative
    •  Headlamps Flash to Pass Inoperative
    •  High Beam Indicator Malfunction
    •  High Mount Stop Lamp Inoperative
    •  Interior Backlighting Does Not Dim
    •  Interior Backlighting Inoperative
    •  License Lamps Inoperative
    •  Marker Lamps Inoperative
    •  Park Lamps Always On
    •  Park Lamps Inoperative
    •  Rear Compartment Lamp Always On
    •  Rear Compartment Lamp Inoperative
    •  Inside Rearview Mirror Lamp Inoperative
    •  Stop Lamps Always On
    •  Stop Lamps Inoperative
    •  Turn Signal Lamps and/or Indicators Always On or Flashing
    •  Turn Signal Lamps and/or Indicators Inoperative