For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle

• | Review Strategy Based Diagnosis

• | Diagnostic Procedure Instructions

### DTC Descriptor

DTC B2652 02: Passenger Compartment Dimming 3 Circuit Short to Ground

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Interior Backlighting Control Control | B2652 02 | 2 | 1 | --
1. Cigar lighter illumination at full intensity and cannot be dimmed or turned Off 2. Cigar lighter illumination 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 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 circuits illuminating the cigar lighter.

### Conditions for Running the DTC

• | The ignition is ON.

• | The headlamps or park lamps ON.

### Conditions for Setting the DTC

The BCM detects a short to ground on the cigar lighter control circuit.

### Action Taken When the DTC Sets

The BCM does not attempt to illuminate the cigar lighter.

### 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

### Circuit/System Verification

Ignition ON, command the Incandescent Dimming Duty Cycle Command test with a scan tool. The commanded brightness by the scan tool should correspond the brightness of the illumination of the E32 Cigar Lighter.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connectors at all components fed by the backlight dimming control circuit terminal 7 (X6).
2. Ignition ON, clear the DTC with a scan tool.
3. Operate the vehicle within the conditions for running the DTC and verify the DTC does not reset.

⇒ | If the DTC resets, test the interior backlighting control circuit for a short circuit to ground. If the circuit test normal, replace the appropriate disconnected component.

4. If all circuits test normal, test or replace the K9 Body Control Module (BCM).

### Repair Instructions

Perform the Diagnostic Repair Verification

• | Cigar Lighter Receptacle Replacement

• | Control Module References