- Symptoms - Lighting

SYMPTOMS - LIGHTING SYSTEMS

IMPORTANT: The following steps must be completed before using the symptom tables.

1. Perform the Vehicle System Check before using the symptom tables in order to verify that all of the following are true:
- There are no DTCs set.
- The body control module (BCM) can communicate via the serial data link. Initial Inspection and Diagnostic Overview
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
Several of the symptom procedures ask for a careful visual/physical check. This step is extremely important; it could lead to correcting a problem without further checks and can save valuable time. These checks include the following:
- Inspect for aftermarket devices which could affect the operation of the Lighting System.
- Inspect the easily accessible or visible system components and harness connectors for obvious damage or conditions which could cause the symptom.
- If only one lamp is inoperative, inspect and repair a poor connection or an open in the power feed or ground circuit before replacing the light bulb.

Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose a symptom that does not set a DTC:
- Backup Lamps Always On
- Backup Lamps Inoperative
- Courtesy Lamps Always On
- Courtesy Lamps Inoperative
- Fog Lamps Always On
- Fog Lamps Inoperative
- Hazard Lamps Inoperative
- Headlamp Low or High Beams Always On
- Headlamps Inoperative - High Beams
- Headlamps Inoperative - Low Beams
- Low and High Beams Headlamps Inoperative
- Headlamps Flash to Pass Inoperative
- High Beam Indicator Inoperative
- Park Lamps Inoperative
- Reading Lamp(s) Inoperative
- Rear Compartment Lamp(s) Inoperative
- Stop Lamps Inoperative
- Turn Signal Lamps and/or Indicators Inoperative