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 B2652 00: Passenger Compartment Dimming 3

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
B+, BCM X2 Terminal 2 | B2652 00 | B2652 00 | -- | --
I/P Lamps Control | B2652 00 | 2 | 1 | --
1. Interior Backlighting Does Not Dim 2. Interior Backlighting Inoperative

### Circuit/System Description

The body control module (BCM) supplies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp 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 I/P 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 components listed below.

• | Hazard Switch

• | I/P Cluster

• | Power Window Switches

• | Sunroof Switch

• | Garage Door Opener Transmitter

### 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 instrument panel lamps control circuit.

### Action Taken When the DTC Sets

The BCM does not attempt to illuminate the instrument panel lamps.

### Conditions for Clearing the DTC

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 Verification

Ignition ON, command Incandescent Dimming ON with a scan tool. The Incandescent Relay Command parameter should display On and the Incandescent Dimming should illuminate.

### Circuit/System Testing

1. Ignition OFF, disconnect the X2 harness connector at the BCM.
2. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuits listed below for a short to ground.

• | Instrument panel lamp control circuit terminal 3 X2

• | Instrument panel lamp control circuit terminal 3 X6

3. Ignition OFF, connect the X2 harness connector to the BCM.
4. Disconnect the harness connectors at all components fed by the BCM control circuits listed below.

• | Instrument panel lamp control circuit terminal 3 X2

• | Instrument panel lamp control circuit terminal 3 X6

5. Ignition ON, clear the DTC with a scan tool.
6. Operate the system within the Conditions for Running the DTC and verify the DTC does not reset.

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

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

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Hazard Warning Switch Replacement

• | Sunroof Switch Replacement

• | Garage Door Opener Replacement

• | Control Module References for BCM replacement, setup, and programming