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
--- | --- | --- | --- | ---
I/P Lamps Supply Voltage | B2652 00 | 2 | 1 | --
1. Interior Backlighting Does Not Dim 2. Interior Backlighting Inoperative

### Circuit/System Description

Voltage for the interior backlighting components is supplied from the CHMSL/DIMR Fuse in the instrument panel I/P electrical center to the body control module (BCM).

The BCM applies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimming switch, which is part of the headlamp switch. When the dimming switch is placed in the desired position, the dimmed voltage setting is applied from the interior lamp dimming switch through the I/P dimming return circuit to the BCM. The BCM then applies the dimmed voltage to the I/P lamps supply voltage circuit and they dim to the correct level.

The IP lamps are located in the following components:

• | Cigar lighter

• | Driver Information Center DIC switch

• | Door lock switches

• | Fog Lamp switch

• | Headlamp switch (turn signal multifunction switch)

• | Hazard switch

• | HVAC Control

• | Rear HVAC Control if equipped

• | I/P cluster

• | Power window switch

• | Power mirror switches

• | PRNDL

• | Radio

• | Rear Seat Audio if equipped

• | Steering Wheel Controls

• | Sunroof switch

• | Sunshade switch

• | TCS switch

• | Universal garage door opener switch

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

The BCM receives a ground signal on the I/P lamps supply voltage circuit.

### Action Taken When the DTC Sets

The I/P lamps are not illuminated

### Conditions for Clearing the DTC

The BCM clears this code from current when the fault is removed from the system.

### Reference Information

#### Schematic Reference

Interior Lights Dimming Schematics

#### Connector End View Reference

Lighting Systems Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

• | Scan Tool Output Controls

• | Scan Tool Data List

• | Scan Tool Data Definitions

### Circuit/System Verification

Ignition ON, cover the ambient light sensor, vary the interior lamp dimming switch from dim to full bright. The I/P lamps should dim and then become full bright.

### Circuit/System Testing

1. Clear the DTC. Headlamp switch OFF, disconnect all interior lamps dimming related components. Refer to the circuit/system verification for all components that contain the I/P lamps. Verify the DTC B2652 does not set

⇒ | If the DTC resets then test for a short to ground in the I/P lamps supply voltage circuit. If the circuit/connections test normal replace the BCM.

2. Reconnect each component one at a time and test for the DTC B2652.

⇒ | If the DTC resets, then replace that component.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Multifunction Turn Signal Switch Housing Replacement

• | Hazard Warning Switch Replacement

• | Instrument Panel Lamp Dimmer Switch Replacement

• | Automatic Transmission Control Indicator Replacement

• | Sunroof Switch Replacement

• | Driver Information Display Switch Replacement

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