GM Service Manual Online
For 1990-2009 cars only

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

  1. Perform Diagnostic System Check - Lighting Systems before using the Symptom Tables in order to verify that all of the following are true:
  2. • There are no DTCs set.
    • The control module(s) is operating properly.
  3. Review the system operation in order to familiarize yourself with the system functions. Refer to Lighting System Description .

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
    •  Battery Rundown Protection Inoperative
    •  Courtesy Lamps Always On
    •  Courtesy Lamps Inoperative
    •  Courtesy Lamps Inoperative with Instrument Panel Dimmer Switch
    •  Courtesy Lamps Inoperative with Doors Open
    •  Courtesy/Reading Lamps Always On
    •  Courtesy/Reading Lamps Inoperative
    •  Daytime Running Lamps (DRL) Headlamps Inoperative
    •  Fog Lamps Always On
    •  Rear Fog Lamps Always On
    •  Fog Lamps Inoperative
    •  Rear Fog Lamps Inoperative
    •  Fog Lamp Indicator Inoperative
    •  Fog Lamp Indicator Inoperative
    •  Fog Lamp Indicator Always On
    •  Rear Fog Lamp Indicator Always On
    •  Hazard Lamps Inoperative
    •  Headlamp Low or High Beams Always On
    •  Headlamps Inoperative - Low Beams
    •  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
    •  Instrument Panel Compartment Lamp Inoperative
    •  Instrument Panel Compartment Lamp Always On
    •  Vanity Mirror Lamp Inoperative
    •  Instrument Panel Lamps Do Not Dim
    •  Instrument Panel Lamps Inoperative - One
    •  Instrument Panel Lamps Erratic with Dimmer Switch
    •  Instrument Panel Lamps or Vacuum Fluorescent Displays Inoperative
    •  Park Lamps Always On
    •  Park Lamps Inoperative
    •  Personalization Mode Inoperative
    •  Roof Rail Courtesy/Reading Lamp Always On
    •  Roof Rail Courtesy/Reading Lamp Inoperative
    •  Stop Lamps Inoperative
    •  Stop Lamps Always On
    •  Trailer Towing Indicator Always On
    •  Trailer Towing Indicator Inoperative
    •  Turn Signal Lamps Inoperative
    •  Turn Signal Lamps Inoperative - Left or Right Side
    •  Turn Lamps Always On
    •  Turn Signal Indicators Inoperative
    •  Vacuum Fluorescent Displays Do Not Change Intensity - All
    •  Vacuum Fluorescent Display Do Not Dim with Park Lamps On