A Symptoms - Lighting Systems

IMPORTANT: The following steps must be completed before using the symptom tables.
1. Perform A 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:
- Interior Lighting System Description
- Headlights Circuit Description
- Headlights/Daytime Running Lights (DRL) Circuit Description
- Exterior Lights Circuit Description (Domestic) or Exterior Lights Circuit Description (VE1)
- Backup Lights Circuit Description (Domestic)
- Backup Lights Circuit Description (VE1)
- 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 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 (Domestic)
- Backup Lamps Inoperative (VE1)
- Backup Lamp Inoperative - One Lamp (Domestic)
- Backup Lamp Inoperative - One Lamp (VE1)
- Component Illumination Lamps Inoperative
- Courtesy or Dome Lamps Always On
- Courtesy or Dome Lamps Inoperative
- Courtesy/Reading Lamps Inoperative
- Daytime Running Lamps (DRL) Headlamps Always On
- Daytime Running Lamps (DRL) Headlamps Inoperative
- Hazard Lamps Inoperative (Domestic)
- Hazard Lamps Inoperative (VE1)
- Headlamp and Panel Dimmer Switch 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
- Headlamps Inoperative - Low and High Beams
- Headlamps, Daytime Running Lamps (DRL) On With Park Brake Applied
- High Beam Indicator Inoperative
- High Beam On with Headlamp Switch Off
- Illuminated Entry Lamps Inoperative
- IP Compartment Lamp Inoperative
- Vanity Mirror Lamp(s) Inoperative
- Instrument Cluster Illumination Lamps Always On
- Instrument Cluster Illumination Lamps Inoperative
- Park, Tail and Side Marker Lamps Inoperative (Domestic)
- Park, Tall and Side Marker Lamps Inoperative (VE1)
- Stop Lamps Inoperative (Domestic)
- Stop Lamps Inoperative (VE1)
- Stop Lamps Inoperative - One (Domestic)
- Stop Lamps Inoperative - One (VE1)
- Stop Lamps Always On (Domestic)
- Stop Lamps Always On (VE1)
- Turn Signal Lamps Inoperative (Domestic)
- Turn Signal Lamps Inoperative (VE1)
- Turn Signal Lamps Inoperative - Left or Right Side (Domestic)
- Turn Signal Lamps Inoperative - Left or Right Side (VE1)
- Turn Signal Indicators Inoperative (Domestic)
- Turn Signal Indicators Inoperative (VE1)

For a description of the RPO Code(s) shown in this article/images refer to the RPO Code List found at Vehicle/Application ID Application and ID