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
--- | --- | --- | --- | ---
CHMSL/DM/LAMP Fuse B+ | B2652 00 | B2652 00 | 1 | --
I/P Lamps Control | B2652 00 | 1 | 1 | --
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 B2652 00 will set for the following conditions:

• | The BCM detects a short to ground in the I/P lamps dimmer switch signal circuit.

• | The BCM detects a short to ground or an open/high resistance in the CHMSL/DM/LAMP fuse B+ circuit.

### Action Taken When the DTC Sets

The BCM will not DIM or illuminate any I/P lamps supplied by the I/P lamps dimmer switch signal 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 X2 harness connector at the BCM.
2. 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.

3. Ignition OFF, connect the X2 harness connector at the BCM.
4. Ignition ON, with a scan tool clear all DTCs.
5. Ignition OFF, disconnect the harness connector at the hazard switch.
6. Ignition ON, operate the vehicle within the conditions for running the DTC and verify the DTC does not reset.

⇒ | If the DTC resets, test the signal circuit terminal I for a short to ground. If the circuit tests normal, replace the BCM.

7. If all circuits test normal, test or replace the hazard switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Hazard Warning Switch Replacement

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