GM Service Manual Online
For 1990-2009 cars only
  1. Perform the 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) can communicate via the serial data link.
  3. Review the system operation in order to familiarize yourself with the system functions. Refer to:
  4. •  Headlights Circuit Description
    •  Headlights/Daytime Running Lights (DRL) Circuit Description
    •  Fog Lights Circuit Description
    •  Exterior Lights Circuit Description
    •  Backup Lamp Circuit Description
    •  Interior Lights Circuit Description
    •  Trailer/Brake Controller Wiring Information

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
    •  Cargo Lamp Always On
    •  Cargo Lamp Inoperative
    •  CARGO LAMP ON Message Always On
    •  CARGO LAMP ON Message Inoperative
    •  Clearance Lamps Inoperative
    •  Courtesy Lamps Inoperative
    •  Courtesy or Dome Lamps Always On
    •  Courtesy or Dome Lamps Inoperative
    •  Courtesy Lamps Inoperative with Instrument Panel Dimmer Switch
    •  Courtesy or Reading Lamps Inoperative with Lamp Switch
    •  Dome Lamps Inoperative with Left Front Door Open
    •  Dome Lamps Inoperative with Instrument Panel Dimming Switch
    •  Daytime Running Lamps (DRL) Headlamps Always On
    •  Daytime Running Lamps (DRL) Headlamps Inoperative
    •  Exterior Courtesy Lamps Always On
    •  Exterior Courtesy Lamps Inoperative
    •  Fog Lamp Indicator Inoperative
    •  Fog Lamps Always On
    •  Fog Lamps Inoperative - All
    •  Fog Lamp Switch Illumination Lamp Inoperative
    •  Hazard Lamps Inoperative
    •  Headlamps Inoperative - Left Low Beam
    •  Headlamps Inoperative - Right Low Beam
    •  Headlamps Inoperative - Low Beams
    •  Headlamps Inoperative - Left High Beam
    •  Headlamps Inoperative - Right High Beam
    •  Headlamps Inoperative - High Beams
    •  Headlamps Flash to Pass Inoperative
    •  Low and High Beams Headlamps Inoperative
    •  Headlamps Inoperative in Low Light Conditions
    •  Headlamps On in Daylight Conditions
    •  Headlamps Do Not Switch Intensity
    •  Headlamps, Daytime Running Lamps (DRL) On With Park Brake Applied
    •  High Beam Indicator Always On
    •  High Beam Indicator Inoperative
    •  Instrument Cluster Illumination Lamps Inoperative
    •  Instrument Panel Compartment Lamp Inoperative
    •  Vanity Mirror Lamp Inoperative
    •  Vanity Mirror Lamp Always On
    •  Underhood Lamp Inoperative
    •  Instrument Panel Lamps Do Not Dim
    •  Instrument Panel Lamps Inoperative
    •  Window Switch Lamp Inoperative
    •  Lamps Inoperative - Switch
    •  License Lamps Inoperative
    •  Park Lamps Inoperative
    •  Park Lamps Inoperative - Front
    •  Park Lamp Inoperative - Left Side Front
    •  Park Lamp Inoperative - Right Side Front
    •  Side Marker Lamp Inoperative - One Lamp
    •  Stop Lamps Inoperative
    •  Stop Lamps Inoperative - Center High Mounted
    •  Stop Lamps Always On
    •  Tail Lamp Inoperative - Left Rear
    •  Tail Lamps Inoperative - Right Rear
    •  Turn Signal Lamps Inoperative
    •  Turn Signal Lamp Inoperative - Left Side Front
    •  Turn Signal Lamp Inoperative - Right Side Front
    •  Turn Signal Lamps Inoperative - Left or Right Side
    •  Turn Signal Lamps Inoperative - Left Side Rear
    •  Turn Signal Lamp Inoperative - Right Side Rear
    •  Turn Signal Indicators Inoperative - Left Side
    •  Turn Signal Indicators Inoperative - Right Side
    •  Vacuum Fluorescent Displays Do Not Dim with Instrument Panel Dimmer Switch