DTC B1837

Diagnostic Instructions 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. DTC Descriptors DTC B1837 LED Backlight Dimming Control 1 Refer to Symptom Byte List for symptom byte information. Diagnostic Fault Information

Circuit	Circuit Function	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performan
6817	Control	B1837 11	B1837 13	B1837 12	—
*	Ground	—	1	—	—
1. Interior Backlighting Malfunction *. Refer to the schematic to identify the appropriate ground circuits

Circuit/System Description All interior backlighting turns on at the dimming level indicated by the dimmer switch. The body control module (BCM) interprets the signal and responds by applying pulse width modulated (PWM) voltage to the backlight dimming control circuits illuminating all components with interior backlighting to the appropriate intensity. Conditions for Running the DTC Battery voltage must be between 9-16 V. Conditions for Setting the DTC DTC B1837 11 The BCM detects a short to ground on circuit 6817. DTC B1837 12 The BCM detects a short to voltage on circuit 6817. DTC B1837 13 The BCM detects an open/high resistance control circuit 6817. Actions Taken When the DTC Sets The BCM will disable the LED backlight dimming control circuits. Conditions for Clearing the DTC Conditions for Clearing the DTC The condition responsible for setting the DTC no longer exists. A history DTC will clear once 40 consecutive malfunction–free ignition cycles have occurred. Reference Information Schematic Reference Interior Lights Dimming Schematics Connector End View Reference Master Electrical Component List Description and Operation Interior Lighting Systems Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References for scan tool information Circuit/System Testing

Note

Each component may need to be disconnected to isolate a short to voltage, short to ground, or an open/high resistance. Use the schematics to identify the following: Courtesy lamps the vehicle is equipped with Each component’s control and ground circuit terminals Component locations on control circuit 6817

1. Ignition/vehicle off, disconnect the X5 connector at the K9 Body Control Module.
2. Connect a 3 A fused jumper wire between control circuit terminal 6 and B+.

Note

Refer to the schematic to identify the appropriate components on circuit 6817.

3. Verify the backlighting on the appropriate components turn on and off when connecting and disconnecting the jumper wire. ⇒ If a component backlighting is always off and the jumper fuse is OK. 3.1. Test the appropriate ground circuit for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit or ground connection. ⇓ If an open/high resistance is not found. 3.2. Test circuit 6817 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found. 3.3. Replace the appropriate accent/courtesy lamp. ⇒ If a component backlighting is always off and the jumper fuse is open 3.1. Test circuit 6817 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found. 3.2. Replace the appropriate accent/courtesy lamp. ⇒ If a component backlighting is always on 3.1. Test circuit 6817 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found. 3.2. Replace the appropriate accent/courtesy lamp. ⇓ If the accent lamps turn on and off
4. Replace the K9 Body Control Module. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Lighting Component Replacement Reference Control Module References for BCM replacement, programming, and setup