B2625

DTC B2625

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC B2625 02
- Display Dimming Pulse Width Modulation Output Circuit Short to Ground

Diagnostic Fault Information





Circuit/System Description

The dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The body control module (BCM) supplies a reference voltage to the backlight dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, the dimmed voltage setting is applied through the dimmer switch and the dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the backlight lamp control circuit and the LED dimming control circuit illuminating the components to the requested level.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

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

Actions Taken When the DTC Sets

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

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 (Interior Lights Dimming Schematics)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Interior Lighting Systems Description and Operation (Interior Lighting Systems)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, park lamps ON, vary the interior backlight dimming from low to full bright by using the dimmer switch. The LED on all components should dim and then become full bright.

Circuit/System Testing

Note: Each component on backlighting control circuit may need to be disconnected to isolate a short to voltage or short to ground. Use the schematic to identify the following:

* All backlighting components that the vehicle is equipped with
* Component locations on the backlighting dimming control circuit
* Each component's control and ground circuit terminals

1. Ignition OFF, disconnect the harness connector at any component on the interior backlighting control circuit.
2. Scan tool disconnected, interior lamps OFF, doors CLOSED, test for less that 10 Ohms between the ground circuit terminal and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal and ground.
4. Ignition ON, command the LED Backlight Dimming ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.

5. If all circuits test normal, test or replace the appropriate component.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Refer to the appropriate replacement procedure for the component causing the condition.
* Control Module References (Programming and Relearning) for BCM replacement, setup and programming