A Symptoms - Lighting Systems

1. Perform the 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. Diagnostic System Check - Lighting Systems
2. Review the system operation in order to familiarize yourself with the system functions. Refer to the following:
- 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 Diagnostic Aids.
- 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 Diagnostic Aids.

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
- Clearance Lamps Inoperative
- Courtesy Lamps Always On (Without RPO Y91)
- Courtesy Lamps Always On (With RPO Y91)
- Courtesy Lamps Inoperative (Without RPO Y91) or Courtesy Lamps Inoperative (With RPO Y91)
- Daytime Running Lamps (DRL) Always On
- Daytime Running Lamps (DRL) Inoperative
- Daytime Running Lamps (DRL) On with Park Brake Applied
- Exterior Courtesy Lamp(s) Always On
- Exterior Courtesy Lamp(s) Inoperative
- Fog Lamp Indicator Inoperative (Front) or Fog Lamp Indicator Inoperative (Export, Rear)
- Fog Lamps Always On (Front) or Fog Lamps Always On (Export, Rear)
- Fog Lamps Inoperative (Front) or Fog Lamps Inoperative (Export, Rear, Utility)
- Hazard Lamps Inoperative
- Headlamps Inoperative - Low Beams
- Headlamps Inoperative - High Beams
- Headlamps Inoperative - Low and High Beams
- Headlamps Inoperative - Flash to Pass
- Headlamps Inoperative in Low Light Conditions
- Headlamps On in Daylight 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
- Park Lamps Inoperative
- Reading Lamp(s) 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(s) Always On
- 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