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 - Lighting Systems before using the Symptom Tables in order to verify that all of the following are true:
      • There are no DTCs set.
      • The control module(s) can communicate via the serial data link.
    • Review the system operation in order to familiarize yourself with the system functions. Refer to Lighting System 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
    •  Backup Lamp Inoperative - One Lamp
    •  Courtesy or Dome Lamps Always On
    •  Courtesy Lamps Inoperative
    •  Daytime Running Lamps (DRL) Headlamps Always On
    •  Daytime Running Lamps (DRL) Headlamps Inoperative
    •  Fog Lamp Indicator Inoperative
    •  Fog Lamps Always On
    •  Fog Lamps Inoperative
    •  Fog Lamps Inoperative - One
    •  Hazard Lamps Always On
    •  Hazard Lamps Inoperative
    •  Headlamps Inoperative - Low Beams
    •  Headlamps Inoperative - Low Beams with Windshield Wipers On
    •  Headlamps - Low Beams On with Headlamp Switch Off
    •  Headlamps Inoperative - High Beams
    •  Headlamps Flash to Pass Inoperative
    •  Headlamps Inoperative - One Lamp
    •  Low and High Beams Headlamps Inoperative
    •  High Beam Indicator Always On
    •  High Beam Indicator Inoperative
    •  High Beam On with Headlamp Switch Off
    •  Instrument Panel Compartment Lamp Inoperative
    •  Vanity Mirror Lamp Inoperative
    •  Rear Compartment Lamp Inoperative
    •  Incandescent Lamps Always On
    •  Incandescent Lamps Inoperative
    •  Lamps Inoperative - Left and/or Right Side Front Switches
    •  License Lamps Inoperative
    •  Park Lamps Always On
    •  Park Lamps Inoperative
    •  Reading Lamp Inoperative
    •  Stop Lamps Inoperative
    •  Stop Lamps Always On
    •  Turn Signal Lamps Inoperative
    •  Turn Signal Lamps and Indicators Inoperative - One Side
    •  Turn Signal Indicators Inoperative
    •  Turn Signal Lamps Always On - One Side
    •  Twilight Sentinel Inoperative
    •  Vacuum Fluorescent Displays Inoperative - All