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

The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The instrument panel dimmer switch provides a voltage signal to the body control module (BCM) that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The BCM provides a low reference, signal, and B+ voltage reference circuits to the instrument panel dimmer switch. When the instrument panel dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated voltage through the LED backlight dimming control circuit illuminating the dome lamp switch, all wheel drive switch, lane departure warning switch, park assist switch, and driver and passenger door lock switch amber LED’s to the requested level of brightness.

• Battery voltage must be between 9–16 V.
• Park lamps ON.

The BCM detects a short to ground in the indicator dimming control circuit terminal 5 X1.

The dome lamp switch, all wheel drive switch, lane departure warning switch, park assist switch, and driver and passenger door lock switch amber indicators are inoperative.

• The condition responsible for setting the DTC no longer exists.
• A history DTC will clear once 100 consecutive malfunction–free ignition cycles have occurred.

Interior Lights Dimming Schematics

Master Electrical Component List

Interior Lighting Systems Description and Operation

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

Control Module References for scan tool information

Note: Each component with backlighting may need to be disconnected to isolate a short to voltage or short to ground. Use the schematics to identify the following:

• Backlighting components the vehicle is equipped with
• Each component's control and ground circuit terminals
• Component locations on the backlighting control circuit

1. Ignition OFF, disconnect the harness connector at the appropriate switch listed below.
• A98 Front Overhead Console Assembly
• S126 Drive Mode Select Switch
• S107 Parking Assist On/Off Switch (UFQ)
• S13D Door Lock Switch – Driver
• S13P Door Lock Switch – Passenger
2. Ignition ON, place the instrument panel dimmer switch in the HIGH position for high backlighting intensity.
3. Verify a test lamp illuminates between the appropriate control circuit terminal listed below and ground.
• A98 Front Overhead Console Assembly terminal 18
• S126 Drive Mode Select Switch terminal 5 (-EPH)
• S126 Drive Mode Select Switch terminal 8 (EPH)
• S107 Parking Assist On/Off Switch terminal 5 (UFQ)
• S13D Door Lock Switch – Driver terminal 5
• S13P Door Lock Switch – Passenger terminal 5
• If the test lamp does not illuminate
1. Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K9 Body Control Module.
• If the test lamp illuminates
4. Place the instrument panel dimmer switch in the LOW position for low backlighting intensity.
5. Verify a test lamp does not illuminate at FULL intensity between the appropriate control circuit terminal listed below and ground.
• A98 Front Overhead Console Assembly terminal 18
• S126 Drive Mode Select Switch terminal 5 (-EPH)
• S126 Drive Mode Select Switch terminal 8 (EPH)
• S107 Parking Assist On/Off Switch terminal 5 (UFQ)
• S13D Door Lock Switch – Driver terminal 5
• S13P Door Lock Switch – Passenger terminal 5
• If the test lamp illuminates at full intensity
1. Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON.
2. Test for less than 1 V between the control circuit terminal and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K9 Body Control Module.
• If the test lamp does not illuminate at full intensity
6. Test or replace the inoperative component.

Perform the Diagnostic Repair Verification after completing the repair.

• Door Lock Switch Replacement - Driver Side
• Door Lock Switch Replacement - Passenger Front
• Floor Console Accessory Function Switch Replacement
• Control Module References for BCM replacement, programming, and setup