For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle

• | Review Strategy Based Diagnosis

• | Diagnostic Procedure Instructions

### DTC Descriptor

DTC B2625 02: Display Dimming Pulse Width Modulation (PWM) Output Circuit Short to Ground

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Interior Backlighting Control | B2625 02 | 2 | 1 | --
1. Multifunction switch at full intensity and cannot be dimmed or turned off 2. Multifunction switch do not illuminated when switched features activated

### Circuit/System Description

The body control module (BCM) supplies a voltage reference through the instrument panel cluster lamps dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness 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 circuit, the backlight lamp control circuit, and the LED dimming control circuit illuminating the LED and instrument panel cluster lamps panel lamps.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

The BCM detects a short to ground on the LED dimming control circuit.

### Action Taken When the DTC Sets

The BCM will not attempt to illuminate the LED indicator lamps when a short circuit to ground accours.

### 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, switch ON exterior lighting, vary the interior lamp dimming which is located on the S30 Headlamp Switch from dim to full bright. The LED of the S48D Multifunction Switch - I/P and S48D Multifunction Switch - I/P should dim and then become full bright.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the S48D Multifunction Switch - I/P and S48D Multifunction Switch - I/P of the LED backlight dimming control circuit terminal 5 (X1) at K9 Body Control Module (BCM).
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

• | Instrument Panel Multifunction Switch Replacement

• | Control Module References