A Symptoms - Lighting Systems

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:
^ There are no DTCs set.
^ The control module(s) can communicate via the serial data link.
2. 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:
^ Exterior Lighting Systems Description and Operation
^ Interior Lighting Systems Description and Operation Diagnostic System Check - Lighting Systems

Visual/Physical Inspection
^ Inspect for aftermarket devices which could affect the operation of the lighting system. Refer to Checking Aftermarket Accessories in Diagrams.
^ 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 and Poor Connections in Diagrams.

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
^ Courtesy Lamps Always On
^ Courtesy Lamps Inoperative
^ Daytime Running Lamps (DRL) Inoperative (Standard) or Daytime Running Lamps (DRL) Inoperative (Envoy/Diamond Edition W/HID) or Daytime Running Lamps (DRL) Inoperative (ZR2)
^ Daytime Running Lamps (DRL) On with Headlamp Switch On (Standard) or Daytime Running Lamps (DRL) On with Headlamp Switch On (Envoy/Diamond Edition W/HID) or Daytime Running Lamps (DRL) On with Headlamp Switch On (ZR2)
^ Daytime Running Lamps (DRL) On with Park Brake Applied
^ Fog Lamp Indicator Always On
^ Fog Lamp Indicator Inoperative
^ Fog Lamps Always On (All) or Fog Lamps Always On (Export)
^ Fog Lamps Inoperative (Front) or Fog Lamps Inoperative (Rear)
^ Hazard Lamps Inoperative
^ Headlamps Inoperative - Low and High Beams (Except ZR2) or Headlamps Inoperative - Low and High Beams (ZR2)
^ Headlamps Inoperative - Low Beams (Standard) or Headlamps Inoperative - Low Beams (Envoy and Diamond Edition W/HID)
^ Headlamps Inoperative - High Beams (Standard) or Headlamps Inoperative - High Beams (Envoy/Diamond Edition W/HID)
^ Headlamps Inoperative in Low Light Conditions
^ Headlight Leveling Inoperative
^ High Beam Indicator Always On
^ High Beam Indicator Inoperative
^ Interior Backlighting Does Not Dim
^ Interior Backlighting Inoperative
^ IP Compartment Lamp Inoperative
^ IP Compartment Lamp Always On
^ License Lamps Inoperative
^ Marker Lamps Inoperative
^ Park Lamps Inoperative
^ Tail, Marker, and License Lamps Always On
^ Tail, Marker, and License Lamps Inoperative
^ Repeater Lamps Inoperative
^ Stoplamps Always On
^ Stoplamps Inoperative (Domestic) or Stoplamps Inoperative (Export)
^ Taillamps Inoperative
^ Turn Signal Lamps and/or Indicators Always On or Flashing
^ Turn Signal Lamps and/or Indicators Inoperative
^ Underhood Lamp Inoperative
^ Vanity Mirror Lamp(s) Inoperative

"For a description of the RPO Code(s) shown in this article or any of the images therein, refer to the RPO Code List found at Vehicle/Application ID". RPO Codes