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 body control module (BCM) supplies a reference voltage to the backlight dimmer switch, which is part of the headlamp switch. When the backlight dimmer switch is placed in a desired brightness position, reference voltage is applied through the backlight dimmer switch resistor ladder to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage to the backlight lamp control circuit, and the LED dimming control circuit illuminating the LEDs and the components listed below, if equipped:
* Seat heating/venting/cooling switch - driver
* Seat heating/venting/cooling switch - passenger
* Multifunction switch - instrument panel 1
* Multifunction switch - instrument panel 2
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 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 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 Views)
Description and Operation
Interior Lighting Systems Description and Operation (Interior Lighting Systems Description and Operation)
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, switch ON exterior lighting, vary the interior backlight from dim to full bright by using the dimmer switch. The LED of the S31D Seat Heating and Cooling Switch - Driver, S31P Seat Heating and Cooling Switch - Passenger, S48C Multifunction Switch 1 - Instrument Panel and S48D Multifunction Switch 2 - Instrument Panel should dim and then become full bright.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate inoperative switch.
2. Test for less than 5 ohm between the ground circuit terminal 2 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Disconnect the harness connector X1 at the K9 Body Control Module.
4. Test for less than 0.3 V between the appropriate inoperative switch terminal 3 and ground.
• If greater than the specified range, test the circuit for a short to voltage. If the circuits test normal, replace the appropriate inoperative switch.
5. Test for greater than 500 kohm between the appropriate multifunction switch terminal 3 and ground.
• If lower than the specified range, test the circuit for a short to ground. If the circuits test normal, replace the appropriate inoperative switch.
6. Test for less than 5 ohm between harness connector K9 Body Control Module terminal 5 X1 and the appropriate inoperative switch terminal 3.
• If greater than the specified range, test the circuit for a for open/high resistance. If the circuits test normal, replace the appropriate inoperative switch.
7. If all circuits test normal, replace the K9 Body Control Module.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Instrument Panel Multifunction Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming