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:

   •  Headlights Circuit Description
   •  Headlights/Daytime Running Lights (DRL) 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 Inoperative
    •  Backup Lamp Inoperative - One Lamp
    •  Courtesy or Dome Lamps Always On
    •  Dome Lamps Inoperative with Left Front Door Open
    •  Dome Lamps Inoperative with Instrument Panel Dimming Switch
    •  Daytime Running Lamps (DRL) Inoperative, Headlamp Switch Operates Normally
    •  Daytime Running Lamps (DRL) Indicator Inoperative
    •  Rear Fog Lamps Always On
    •  Rear Fog Lamps Inoperative
    •  Fog Lamp Switch Illumination Lamp Inoperative
    •  Fog Lamp Indicator Inoperative
    •  Hazard Lamps Inoperative
    •  Headlamps Inoperative - Left Low and High Beam
    •  Headlamps Inoperative - Right Low and High Beam
    •  Headlamps Inoperative - Left Low Beam
    •  Headlamps Inoperative - Right Low Beam
    •  Headlamps Inoperative - Low Beams
    •  Headlamps - Low Beams On with Headlamp Switch Off
    •  Headlamps Inoperative - Left High Beam
    •  Headlamps Inoperative - Right High Beam
    •  Headlamps Inoperative - High Beams
    •  Low and High Beams Headlamps Inoperative
    •  Headlamps, Daytime Running Lamps (DRL) On With Park Brake Applied
    •  Headlamps, Daytime Running Lamps (DRL) On with Headlamp Switch On
    •  Headlight Leveling Inoperative - One Actuator
    •  Headlight Leveling Inoperative
    •  Headlight Leveling Inoperative - Actuator Switch Illuminated
    •  High Beam Indicator Inoperative
    •  Instrument Panel Compartment Lamp Inoperative
    •  Vanity Mirror Lamp Inoperative
    •  Underhood Lamp Inoperative
    •  Instrument Panel Lamps Do Not Dim
    •  Instrument Panel Lamps Inoperative
    •  Window Switch Lamp Inoperative
    •  HVAC Switch Lamp Inoperative
    •  Door Lamp Inoperative - Left Side Front
    •  Door Lamp Inoperative - Right Side Front
    •  License Lamps Inoperative
    •  Park Lamps Inoperative
    •  Park Lamp Inoperative - Left Side Front
    •  Park Lamp Inoperative - Right Side Front
    •  Side Marker Lamp Inoperative - One Lamp
    •  Side Marker Lamps Inoperative
    •  Stop Lamps Inoperative
    •  Stop Lamps Inoperative - One
    •  Stop Lamps Inoperative - Center High Mounted
    •  Stop Lamps Always On
    •  Tail Lamp Inoperative - Left Rear
    •  Tail Lamps Inoperative - Right Rear
    •  Turn Signal Lamp Inoperative - Left Side Front
    •  Turn Signal Lamp Inoperative - Right Side Front
    •  Turn Signal Lamps Inoperative - Left Side Rear
    •  Turn Signal Lamp Inoperative - Right Side Rear
    •  Turn Signal Lamps and Indicators Inoperative - One Side
    •  Turn Signal Indicators Inoperative
    •  Turn Signal Indicators Inoperative - Left Side
    •  Turn Signal Indicators Inoperative - Right Side