Cargo Lamps Malfunction

Cargo 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 Instructionsprovides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit/System Description

The cargo lamp is located on the rear of the vehicles cab exterior and is supplied voltage by a dedicated cargo lamp control circuit. Cargo lamp operation is controlled by placing the I/P dimmer switch in the full up (ON) position. With the I/P dimmer switch in the ON position the dome lamps, footwell lamps, and cargo lamps will illuminate. The following conditions must be met for the cargo lamp to operate:

* Parking brake APPLIED - vehicles equipped with manual transmission
* Transmission in PARK - vehicles equipped with automatic transmission

Diagnostic Aids

Verify proper operation of the courtesy and dome lamps prior to diagnosing a cargo lamp condition.

Reference Information
Schematic Reference

Interior Lights Schematics Interior Lights Schematics
Connector End View Reference

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

Interior Lighting Systems Description and Operation Interior 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 Referencesfor scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate cargo lamp.
2. Test for less than 5 ohm between the ground circuit terminal B and ground.

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

3. Connect a test lamp between the control circuit terminal A and the ground circuit terminal B.
4. Command the Cargo Lamps 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 BCM.
• If the test lamp is always OFF, test the control circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the BCM.

5. If all circuits test normal, replace the appropriate cargo lamp.

Repair Instructions

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

* Headlamp Switch Replacement Service and Repair
* High Mount Stop Lamp Replacement Service and Repair
* High Mount Stop Lamp Bulb Replacement Service and Repair
* Control Module References Control Module Referencesfor BCM replacement, setup, and programming