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.
Circuit/System Description
When the ignition switch is turned to the RUN position, the radio VF display turns ON at maximum brightness. When the park lamps are ON, all incandescent and LED back lighting turn ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. At the same time all VF displays dim to match the indicated dimming level. The panel dimmer switch potentiometer is an input to the body control module (BCM). When the driver selects a dimming setting by moving the I/P dimming switch potentiometer, all incandescent back lighting lamps are provided with a specific voltage. 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
Reference Information
Schematic Reference
Interior Lights Dimming Schematics (Interior Lights Dimming Schematics)
Connector End View Reference
Component Connector End Views (Component Connector End Views)
Description and Operation
Interior Lighting Systems Description and Operation (Interior Lighting Systems Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Programming and Relearning (Programming and Relearning)for scan tool information
Circuit/System Verification
1. Ignition ON, observe the driver door switch while commanding the Driver Door Switch Integrated Sw. Backlighting Test ON and OFF with a scan tool. The switch backlighting should turn ON and OFF between commanded states.
• If the backlighting does not turn On and OFF or remains always ON, replace the driver door lock and side window switch.
2. Ignition ON, observe the driver memory/heated seat switch while commanding the Driver Door Switch Non-Integrated Sw. Backlighting Test ON and OFF with a scan tool. The switch backlighting should turn ON and OFF between commanded states.
• If the backlighting does not turn On and OFF or remains always ON, refer to Front Door Switch Backlighting Circuit Test.
3. Ignition ON, observe the passenger door switch while commanding the Passenger Door Switch Integrated Sw. Backlighting Test ON and OFF with a scan tool. The switch backlighting should turn ON and OFF between commanded states.
• If the backlighting does not turn On and OFF or always remains ON, replace the passenger door lock and side window switch.
4. Ignition ON, observe the passenger heated seat switch while commanding the Passenger Door Switch Non-Integrated Sw. Backlighting Test ON and OFF with a scan tool. The switch backlighting should turn ON and OFF between commanded states.
• If the backlighting does not turn On and OFF or remains always ON, refer to Front Door Switch Backlighting Circuit Test.
5. Ignition ON, observe the scan tool BCM Dimming Control Signal parameter while operating the dimmer switch from high to low. The reading should change from a high percent to a low percent as the switch is rotated.
• If the reading does not change, refer to Dimmer Switch Circuit Test.
• If the scan tool dimmer control operates normal, refer to the Interior Backlighting Circuit Test or the LED Dimming Circuit Test.
Circuit/System Testing
Dimmer Switch Circuit Test
1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Ignition OFF, verify that a test lamp illuminates between the ground circuit terminal 8 and B+.
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Dimming Control Signal parameter is less than 0.1 volts.
• If greater than the specified range, test the signal circuit terminal 13 for a short to voltage. If the circuit tests normal, replace the BCM.
4. Ignition ON, test for B+ between the I/P dimming voltage reference circuit terminal 15 and ground.
• If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
5. Install a 3A fused jumper wire between the signal circuit terminal 13 and the voltage reference circuit terminal 15. Verify the scan tool BCM Dimming Control Signal parameter is greater than 2.6 volts.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
6. If all circuits test normal, test or replace the headlamp switch.
Interior Backlighting Circuit Test
1. Ignition OFF, disconnect the harness connector at the affected component.
2. Ignition OFF, verify that a test lamp illuminates between the listed ground circuit terminal and battery voltage.
* PRNDL lamp terminal B
* Global window switch terminal D
* Transfer case control switch terminal 6
* Headlamp switch terminal 8
* Midgate window switch terminal D
* Sunroof switch terminal C
* Rear window switch terminal E
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the listed backlighting control circuit terminal and ground.
* PRNDL lamp terminal A
* Global window switch terminal E
* Transfer case control switch terminal 5
* Headlamp switch terminal 7
* Midgate window switch terminal E
* Sunroof switch terminal A
* Rear window switch terminal A
4. Command the dimming test high to low with a scan tool. The test lamp should turn from bright to dim when changing between the commanded states.
• 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.
• If the test lamp is always bright, 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 affected component.
LED Dimming Circuit Test
1. Ignition OFF, disconnect the harness connector at the affected component.
2. Ignition OFF, verify that a test lamp illuminates between the listed ground circuit terminal and battery voltage.
* Left steering wheel switch terminal 8
* Right steering wheel switch terminal 1
* Analog clock terminal 2
* Rear wiper/washer switch terminal 1
* DIC switch terminal 5
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the listed LED dimming control circuit terminal and ground.
* Left steering wheel switch terminal 6
* Right steering wheel switch terminal 2
* Analog clock terminal 3
* Rear wiper/washer switch terminal 4
* DIC switch terminal 4
* IPC terminal 8
* Radio terminal 7 X1
4. Command the dimming test high to low with a scan tool. The test lamp should turn from bright to dim when changing between the commanded states.
• 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.
• If the test lamp is always bright, 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 affected component.
Front Door Switch Backlighting Circuit Test
1. Ignition OFF, disconnect the X4 harness connector at the door lock and side window switch.
2. Connect a 3A fused jumper wire between the low reference circuit terminal 4 and ground.
3. Connect a test lamp between the backlight supply voltage circuit terminal 13 and B+. The heated seat switch backlighting should illuminate.
• If the switch backlighting does not illuminate, replace the heated seat switch.
4. If the switch backlighting tests normal, replace the door lock and side window switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Front Seat Heater Switch Replacement (Service and Repair)
* Steering Wheel Control Switch Assembly Replacement (Service and Repair)
* Driver Information Display Switch Replacement (Service and Repair)
* Accessory Switch Replacement (Service and Repair)
* Headlamp Switch Replacement (Service and Repair)
* Programming and Relearning (Programming and Relearning)for BCM, door lock and side window switch, IPC, or radio replacement, programming, and setup.