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) can communicate via the serial data link.
  3. Review the system operation and circuit descriptions that apply to the customer complaint in order to familiarize yourself with the system functions. Refer to the following list:
  4. •  Headlights Circuit Description
    •  Fog Lights Circuit Description
    •  Headlight Leveling Circuit Description
    •  Exterior Lights Circuit Description
    •  Backup Lamp Circuit Description
    •  Interior Lights Circuit Description
    •  Interior Lights Dimming Circuit 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
    •  Backup Lamp Inoperative - One Lamp
    •  Courtesy or Dome Lamps Always On
    •  Courtesy or Dome Lamps Inoperative
    •  Fog Lamp Indicator Inoperative
    •  Fog Lamps Always On
    •  Fog Lamps Inoperative - All
    •  Rear Fog Lamps 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
    •  Headlamps Inoperative in Low Light Conditions
    •  Headlight Leveling Inoperative
    •  High Beam Indicator Always On
    •  High Beam Indicator Inoperative
    •  Instrument Cluster Illumination Lamps Always On
    •  Instrument Cluster Illumination Lamps Inoperative
    •  Instrument Panel Compartment Lamp Inoperative
    •  Vanity Mirror Lamp Inoperative
    •  Underhood Lamp Inoperative
    •  Instrument Panel Lamps Inoperative
    •  License Lamps Inoperative
    •  Marker Lamps Inoperative
    •  Stop Lamps Inoperative
    •  Stop Lamps Inoperative - One
    •  Stop Lamps Inoperative - Center High Mounted
    •  Tail Lamps Inoperative
    •  Tail Lamp Inoperative - Left Rear
    •  Tail Lamps Inoperative - Right Rear
    •  Turn Signal Lamps Inoperative
    •  Turn Signal Lamps Inoperative - Left or Right Side
    •  Turn Signal Indicator Always On - Left Side
    •  Turn Signal Indicator Always On - Right Side
    •  Turn Signal Indicators Inoperative - Left Side
    •  Turn Signal Indicators Inoperative - Right Side