GM Service Manual Online
For 1990-2009 cars only

Important: Review the system operation in order to familiarize yourself with the system functions.

Refer to the circuit description:

   •  Exterior Lighting Systems Description and Operation
   •  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:

    •  Symptoms - Lighting Systems
    •  Backup Lamps Always On
    •  Backup Lamps Inoperative
    •  Courtesy Lamps Always On
    •  Courtesy Lamps Inoperative
    •  Daytime Running Lamps (DRL) Always On
    •  Daytime Running Lamps (DRL) Inoperative
    •  Daytime Running Lamps (DRL) On with Park Brake Applied
    •  Fog Lamps Always On
    •  Fog Lamps Inoperative
    •  Hazard Lamps Inoperative
    •  Headlamp Low or High Beams Always On
    •  Headlamps Inoperative - Low Beams
    •  Headlamps Inoperative - High Beams
    •  Low and High Beams Headlamps Inoperative
    •  Headlight Leveling Inoperative
    •  High Beam Indicator Inoperative
    •  Interior Backlighting Does Not Dim
    •  Interior Backlighting Inoperative
    •  Instrument Panel Compartment Lamp Inoperative
    •  License Lamps Inoperative
    •  Park Lamps Inoperative
    •  Reading 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
    •  Underhood Lamp Inoperative
    •  Vanity Mirror Lamp Always On
    •  Vanity Mirror Lamp Inoperative