Exterior Courtesy Lamps Malfunction

Exterior Courtesy Lamps Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit/System Description

The exterior courtesy lamps are located in the outside rearview mirrors. When the keyless entry control module receives a request from the keyless entry transmitter to unlock the doors, the keyless entry control module will send a serial data message to the BCM, the BCM will then command the left and right door courtesy lamps to illuminate.

Reference Information
Schematic Reference

Exterior Lights Schematics Exterior Lights Schematics
Connector End View Reference

Component Connector End Views Connector End Views By Name
Description and Operation

Exterior Lighting Systems Description and Operation Exterior Lighting Systems
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

Ignition ON, command the Outside Rear View Mirror Courtesy Lamp ON and OFF with a scan tool. The left and right door courtesy lamps should turn ON and OFF when changing between the selected states.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate A9A outside rearview mirror-driver or the A9B outside rearview mirror-passenger.
2. Test for less than 30 ohm between the ground circuit terminal 4 and ground.

• If greater than the specified value, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal 17 and ground.
4. Ignition ON, command the BCM, Exterior Lighting, Front, Outside Rear View Mirror Courtesy Lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.

5. If all circuits test normal, test or replace the A9 outside rearview mirror.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Outside Rearview Mirror Replacement Outside Rearview Mirror Replacement
* Control Module References Control Module References for BCM replacement, setup and programming