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 instrument panel cluster (IPC) receives an input from the I/P dimmer switch. The IPC provides the I/P dimmer switch with battery positive voltage and ground. The I/P dimmer switch is a potentiometer that varies the input signal voltage to the IPC. This input determines the intensity level of the backlighting illumination. The driver may change intensity of the backlighting by positioning the I/P dimmer switch between the minimum and maximum settings. The IPC will default to full intensity if the input from the I/P dimmer switch is not within the specified values. The backlighting illumination intensity is controlled by the IPC by varying the pulse width modulation (PWM) voltage that feeds the dimming signal circuits of the individual lamps. All interior backlighting lamps are permanently grounded.
Reference Information
Schematic Reference
Interior Lights Dimming Schematics Interior Lights Dimming Schematics
Connector End View Reference
Component Connector End Views 5 Bow Lowered Switch (CM7)
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. Ignition ON, observe the scan tool Dim Down Switch parameter while pressing and releasing the dim down switch. The parameter should change between Active and Inactive.
• If the parameter does not change between the selected states, refer to Dimmer Switch Malfunction.
2. Observe the scan tool Dim Up Switch parameter while pressing and releasing the dim up switch. The parameter should change between Active and Inactive.
• If the parameter does not change between the selected states, refer to Dimmer Switch Malfunction.
3. Park lamps ON, command the Dimming Control ON and OFF with a scan tool. The interior backlighting components should turn ON and OFF when changing between the commanded states.
• If the backlighting does not operate as described, refer to Interior Backlighting Malfunction.
Circuit/System Testing
Dimmer Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the I/P dimmer switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 1.
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Verify the scan tool Dim Down Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the IPC.
4. Install a 3 A fused jumper wire between the signal circuit terminal 4 and ground. Verify the scan tool Dim Down Switch parameter is Active.
• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.
5. Verify the scan tool Dim Up Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the IPC.
6. Install a 3A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Dim Up Switch parameter is Active.
• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.
7. If all circuits test normal, test or replace the I/P dimmer switch.
Interior Backlighting Malfunction
Note:
Each back lighted component may need to be disconnected to isolate a short to voltage or short to ground. Use the schematic to identify the following:
* Back lighted components the vehicle is equipped with.
* Component locations on the back lighting dimming control circuit
* Each component's control and ground circuit terminals
1. Ignition OFF, disconnect the harness connector at any component with inoperative backlighting.
2. Ignition OFF, scan tool disconnected, interior lamps OFF, doors CLOSED, test for less than 5 ohms between the ground circuit 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 and ground.
4. Park Lamps ON, command the Dimming 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 OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
5. If all circuits test normal, test or replace the component with the inoperative backlighting.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Head Up Display Switch Replacement Head Up Display Switch Replacement
* Driver Information Display Switch Replacement Service and Repair
* Hazard Warning Switch Replacement Service and Repair
* Dimmer Switch Replacement Service and Repair
* Front Side Door Window Switch Replacement - Left Side Front Side Door Window Switch Replacement - Left Side
* Front Side Door Window Switch Replacement - Right Side Front Side Door Window Switch Replacement - Right Side
* Rear Compartment Lid and Fuel Filler Door Release Switch Replacement Service and Repair
* Folding Top Switch Replacement Service and Repair
* Door Lock Switch Replacement - Driver Side Door Lock Switch Replacement - Driver Side
* Door Lock Switch Replacement - Passenger Front Door Lock Switch Replacement - Passenger Front
* Control Module References Control Module References for BCM, DDM, HVAC, IPC, or PDM replacement, setup, and programming