Interior Backlighting Malfunction
Interior Backlighting 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 body control module (BCM) is responsible for the dimming of the interior lights. The BCM receives a varying signal from the I/P dimmer switch. Based on the position of the I/P dimmer switch, the BCM then supplies the appropriate amount of voltage to the interior lamps. When the headlight switch is turned to the PARK or HEADLAMP position, all incandescent back lighting turns ON at the dimming level indicated by the I/P dimmer switch. When the I/P dimmer switch is moved from MIN to MAX, all VF displays, as well as all incandescent back lighting, respond from minimum intensity to maximum brightness in response to the I/P dimmer switch position.
Reference Information
Schematic Reference
Interior Lights Dimming Schematics Interior Lights Dimming Schematics
Connector End View Reference
Component Connector End Views
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 References for scan tool information
Circuit/System Verification
1. Place the headlamp switch in the PARK position. The interior backlighting should illuminate.
• If the interior backlighting does not illuminate, refer to Interior Backlighting Inoperative.
2. Operate the interior backlighting dimmer switch. The interior backlighting intensity should vary with the position of the switch.
• If the backlighting intensity does not vary, refer to Interior Backlighting Does Not Dim.
Circuit/System Testing
Interior Backlighting Inoperative
1. Ignition OFF, disconnect the harness connector at the dimmer switch.
2. Verify that a test lamp illuminates between the low reference circuit terminal 7 and B+.
• If the test lamp does not illuminate, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
3. Install a 3A fused jumper wire between the reference voltage circuit terminal 2 and the dimming signal circuit terminal 1.
4. Ignition ON, headlamp switch in the PARK position. The interior backlighting should illuminate.
• If the interior backlighting does not illuminate, test the dimming signal circuit terminal 1 for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
5. If all circuits test normal, replace the dimmer switch.
Interior Backlighting Does Not Dim
1. Ignition OFF, disconnect the dimmer switch.
2. Ignition ON, headlamp switch in the PARK position. The interior backlighting should not illuminate.
• If the interior backlighting illuminates, test the dimming signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the BCM.
3. If all circuits test normal, replace the dimmer switch.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Headlamp Switch Replacement Service and Repair
* Control Module References Control Module References for BCM replacement, setup, and programming