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 B2625 00 : Display Dimming Pulse Width Modulation (PWM) Output Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
INADV/PWR/LED Fuse B+ Terminal 2 X3 | 1 | 1 | -- | --
Panel Dimmer Switch DIM Up Signal | 1 | 1 | 1 | --
Panel Dimmer Switch DIM Down Signal | 1 | 1 | 1 | --
Incandescent Backlight Dimming Control Terminal 3 X2 | 1 | 1 | 1 | --
LED Backlight Dimming Control Terminal 18 X3 | B2610 00 | 1 | 1 | --
LED Backlight Dimming Control Terminal 25 X3 | B2625 00 | 1 | 1 | --
Automatic Transmission Shift Lever Ground | -- | 1 | -- | --
Cigar Lighter Console Ground | -- | 1 | -- | --
Cigar Lighter Front Ground | -- | 1 | -- | --
Dome/Reading Lamps Ground | -- | 1 | -- | --
Door Lock/Window Switch Ground | -- | 1 | -- | --
Headlamp and Panel Dimmer Switch Ground | -- | 1 | -- | --
Multifunction Switch - Center Console Ground | -- | 1 | -- | --
Steering Wheel Control Switch Ground | -- | 1 | -- | --
1. Interior Backlighting Malfunction

### Circuit/System Description

The up/down dimmer controls located on the headlamp and panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. Each dimmer control 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) supplies each dimmer control switch with a signal circuit. When either the up or down dimmer control switch is placed in the desired position, the dimmed voltage setting is applied from the appropriate dimmer control switch through the dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the LED backlight dimming control circuits and the interior backlighting components dim to the requested level.

### Conditions for Running the DTC

• | Battery voltage must be between 9-16 volts.

• | Park lamps ON.

### Conditions for Setting the DTC

The BCM detects a short to ground in the LED backlight dimming control circuit terminal 25 X3.

### Actions Taken When the DTC Sets

The BCM will not dim or illuminate any indicators supplied by the LED backlight dimming control circuit terminal 25 X3.

### 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

Headlights/Daytime Running Lights (DRL) 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 center console multifunction switch.
2. Ignition ON, park lamps ON, test for B+ between the control circuit terminal 5 and ground.

⇒ | If not the specified value, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

3. If all circuits test normal, test or replace the center console multifunction switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming