GM Service Manual Online
For 1990-2009 cars only

Important: The following steps must be completed before doing the Symptom tables.

  1. Perform the Diagnostic System Check - Vehicle in Vehicle DTC Information.
  2. • No DTCs are set.
    • The control modules can communicate via the serial data link.
  3. Review the system operation in order to familiarize yourself with the system functions. Refer to Exterior Lighting Systems Description and Operation or 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 in Wiring Systems.
    • Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty 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 list in order to diagnose the symptom:

    •  Backup Lamps Always On
    •  Backup Lamps Inoperative
    •  Courtesy Lamps Always On
    •  Courtesy Lamps Inoperative
    •  Daytime Running Lamps (DRL) 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
    •  Headlamps Flash to Pass Inoperative
    •  Illuminated Entry Lamps Inoperative
    •  Interior Backlighting Does Not Dim
    •  Interior Backlighting Inoperative
    •  Instrument Panel Compartment Lamp Inoperative
    •  Instrument Panel Compartment Lamp Always On
    •  Park, License, and Tail Lamps Always On
    •  Park, License, and Tail Lamps Inoperative
    •  Reading Lamp Always On
    •  Reading Lamp Inoperative
    •  Rear Compartment Lamp Always On
    •  Rear Compartment 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
    •  Vanity Mirror Lamp Always On
    •  Vanity Mirror Lamp Inoperative