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 Descriptors

DTC B2610 01: Passenger Compartment Dimming 1 Circuit Short to Battery
DTC B2610 02: Passenger Compartment Dimming 1 Circuit Short to Ground
DTC B2610 04: Passenger Compartment Dimming 1 Circuit Open

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
LED Interior Backlighting Control (X2) Terminal 8 | B2610 02 | B2610 04 | B2610 01 | --
LED Interior Backlighting Control (X7) Terminal 9 | B2610 02 | B2610 04 | B2610 01 | --
Backlighting Ground | -- | 2 | -- | --
1. Interior Backlighting at Full Intensity and Cannot be Dimmed 2. Interior Backlighting do not Illuminate

### Circuit/System Description

The body control module (BCM) supplies a voltage reference through the instrument panel cluster dimming voltage reference circuit to the instrument panel cluster lamps dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the instrument panel cluster lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the instrument panel lamp control circuit, the backlight lamp control circuit, and the LED dimming control circuit illuminating the LEDs and instrument panel cluster lamps and the components listed below, if equipped:

• | Headlamp switch

• | Electronic stability control switch

• | Automatic transmission shift lever position indicator

• | Steering wheel control switch - left

• | Steering wheel control switch - right

• | Inflatable restraint I/P module indicator

• | Door lock switch - driver

• | Ignition mode switch

• | Intrusion sensor defeat switch

• | Outside rearview mirror switch

• | Rear compartment lid release switch

• | Sunroof switch

• | Sunroof ventilation switch

### Conditions for Running the DTC

• | The ignition is ON.

• | The headlamps or park lamps ON.

### Conditions for Setting the DTC

#### B2610 01

The BCM detects a short to battery on the LED backlight lamp control circuit.

#### B2610 02

The BCM detects a short to ground on the LED backlight lamp control circuit.

#### B2610 04

The BCM detects an open circuit on the LED backlight lamp control circuit.

### Action Taken When the DTC Sets

The BCM will not dim or illuminate any LED backlighting supplied by the backlight lamp control circuits.

### Conditions for Clearing the DTC

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

• | A history DTC will clear once 100 consecutive malfunction 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 Verification

Ignition ON, command the LED Interior Ambient Lighting 1 Duty Cycle test with a scan tool. The commanded brightness by the scan tool should correspond the brightness of the illumination.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connectors at the appropriate inoperative backlighting component.
2. Test for less than 5 Ω between the black wire of the appropriate component and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test LED between the control circuit of the appropriate component and ground.
4. Command with the scan tool the Interior Ambient Lighting 1 Command to full intensity and back again.

⇒ | If the LED cannot be dimmed test the control circuit for a short to voltage or replace the K9 Body Control Module (BCM).

⇒ | If the LED do not emit at all test the control circuit for open/high resistance or replace the K9 Body Control Module (BCM).

5. If all circuit test normal, test or replace the appropriate inoperative backlighting component.

### Repair Instructions

Perform the Diagnostic Repair Verification

• | Instrument Panel Lamp Dimmer Switch Replacement

• | Outside Remote Control Rearview Mirror Switch Replacement

• | Rear Compartment Lid Rear Hinge Replacement

• | Instrument Panel Lamp Dimmer Switch Replacement

• | Steering Wheel Control Switch Assembly Replacement

• | Instrument Panel Inflatable Restraint Module Replacement

• | Door Lock Switch Replacement

• | Ignition and Start Switch Replacement

• | Steering Wheel Inflatable Restraint Module Coil Replacement

• | Control Module References