For 1990-2009 cars

### 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 Descriptor

DTC B2610 00: Passenger Compartment Dimming 1 Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
CHMSL/DM/LAMP Fuse B+ | B2610 00 | B2610 00 | 1 | --
Dimmer Switch B+ Voltage Reference | 1 | 1 | -- | --
Dimmer Switch Signal | B1395 03, B3600 03 | B2652 00, B3600 03 | B1395 07 | --
LED Backlight Dimming Control | B2610 00 | 1 | 1 | --
Dimmer Switch Ground | -- | 2 | -- | --
1. Interior Backlighting Malfunction

### Circuit/System Description

The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level. Ground for the I/P dimmer switch is provided at G201.

### Conditions for Running the DTC

• | Battery voltage must be between 9-16 volts.

• | Park lamps ON.

### Conditions for Setting the DTC

DTC B2610 00 will set when the BCM detects a short to ground in the LED backlight dimming control circuit.

### Action Taken When the DTC Sets

The BCM will not dim or illuminate any indicators supplied by the LED backlight dimming control circuit.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists.

• | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

### Reference Information

#### Schematic Reference

Interior Lights Dimming Schematics

#### Connector End View Reference

Component Connector End Views

#### 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

1. Ignition OFF, disconnect the X4 harness connector at the BCM.
2. Ignition ON, test for B+ between the B+ circuit terminal 4 and ground.

⇒ | If not the specified value, test the B+ circuit for a short to ground or an open/high resistance.

3. Ignition OFF, connect the X4 harness connector at the BCM.
4. Disconnect the X2 harness connector at the BCM.
5. Ignition ON, test for B+ between the B+ circuit terminal 2 and ground.

⇒ | If not the specified value, test the B+ circuit for a short to ground or an open/high resistance.

6. Ignition OFF, connect the X2 harness connector at the BCM.
7. With a scan tool clear the DTC.
8. Ignition OFF, disconnect the harness connectors at the following components fed by the LED backlight dimming control circuit:

• | Driver information center (DIC) switch

• | HVAC control module

• | Rear window wiper/washer/fog lamp switch

• | Radio

• | Steering wheel control switch - left

• | Steering wheel control switch - right

• | Traction control switch (TCS)

• | HVAC Control Module - auxiliary - with C69

9. Operate the vehicle within the conditions for running the DTC and verify the DTC does not reset.

⇒ | If the DTC resets, test the LED backlight dimming control circuit for a short to ground. If the circuits test normal, replace the BCM.

10. Reconnect each component one at a time and verify that the DTC does not reset as current.

⇒ | If the DTC resets as current, test or replace the component responsible for setting the DTC.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Driver Information Display Switch Replacement

• | Rear Window Wiper and Washer Switch Replacement

• | Steering Wheel Control Switch Assembly Replacement

• | Control Module References for BCM, HVAC control module , or Radio replacement, setup, and programming