DTC B2625

 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 has overviews of all diagnostic categories.
 DTC Descriptor

 DTC B2625 02

Display Dimming Pulse Width Modulation Output Circuit Short to Ground

 Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Display Dimming Control

 B2625 02

 2

 1

 -
1. Switch illuminated when switched features Not activated.

2. Switch do not illuminate when switched features Activated.


 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:


• Headlamp Switch
• Multifunction Switch - Center Console
• Multifunction Switch 1 - Instrument Panel (Base)
• Multifunction Switch 1 - Instrument Panel (Uplevel)
• Multifunction Switch 2 - Instrument Panel
• Cigarette Lighter Receptacle
• Head-Up Display Switch
• Park Brake Switch
• Steering Wheel Air Bag Coil
• Night Panel Switch
 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

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 information on diagnostic tools

 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 B80 Park Brake Switch, S48C Multifunction Switch 1 - Instrument Panel, S48D Multifunction Switch 2 - Instrument Panel, S48E Multifunction Switch - Center Console, E32 Cigarette Lighter Receptacle, S30 Headlamp Switch, S111 Night Panel Switch, S27 Head-Up Display Switch, and X85 Steering Wheel Air Bag Coil should dim and then become full bright.

 Circuit/System Testing


1. Ignition OFF, disconnect the harness connector one of the following components:
• S30 Headlamp Switch
• S48E Multifunction Switch - Center Console
• S48C Multifunction Switch 1 - Instrument Panel (Base)
• S48C Multifunction Switch 1 - Instrument Panel (Uplevel)
• S48D Multifunction Switch 2 - Instrument Panel
• E32 Cigarette Lighter Receptacle
• S27 Head-Up Display Switch
• X85 Steering Wheel Air Bag Coil
• B80 Park Brake Switch
• S111 Night Panel Switch
2. Test for less than 5 Ω between the ground circuit terminals listed below and ground:
• S30 Headlamp Switch Terminal X1 6
• S48E Multifunction Switch - Center Console X1 2
• S48C Multifunction Switch 1 - Instrument Panel Terminal X1 1 (Base)
• S48C Multifunction Switch 1 - Instrument Panel Terminal X1 X1 5 (Uplevel)
• S48D Multifunction Switch 2 - Instrument Panel Terminal X1 1
• E32 Cigarette Lighter Receptacle Terminal X1 C
• S27 Head-Up Display Switch Terminal X1 2
• X85 Steering Wheel Air Bag Coil Terminal X1 2
• B80 Park Brake Switch Terminal X1 8
• S111 Night Panel Switch Terminal X1 2
3. If greater than the specified range, test the ground circuit for an open/high resistance.
4. Disconnect each remaining component and test for less than 5 Ω between the ground circuit terminal and ground.
5. If greater than the specified range, test the ground circuit for an open/high resistance.
6. Disconnect the harness connector X2 at the K9 Body Control Module.
7. Test for less than 0.3 V between the appropriate multifunction switch terminal listed below and ground:
• S30 Headlamp Switch Terminal X1 7
• S48E Multifunction Switch - Center Console X1 1
• S48C Multifunction Switch 1 - Instrument Panel Terminal X1 2 (Base)
• S48C Multifunction Switch 1 - Instrument Panel Terminal X1 X1 10 (Uplevel)
• S48D Multifunction Switch 2 - Instrument Panel Terminal X1 10
• E32 Cigarette Lighter Receptacle Terminal X1 B
• S27 Head-Up Display Switch Terminal X1 5
• X85 Steering Wheel Air Bag Coil Terminal X1 6
• B80 Park Brake Switch Terminal X1 6
• S111 Night Panel Switch Terminal X1 2
8. If greater than the specified range, test the circuit for a short to voltage. If the circuits test normal, replace the appropriate switch.
9. Test for greater than 500 K.Ω between the appropriate switch terminal listed below and ground:
• S30 Headlamp Switch Terminal X1 7
• S48E Multifunction Switch - Center Console X1 1
• S48C Multifunction Switch 1 - Instrument Panel Terminal X1 2 (Base)
• S48C Multifunction Switch 1 - Instrument Panel Terminal X1 X1 10 (Uplevel)
• S48D Multifunction Switch 2 - Instrument Panel Terminal X1 10
• E32 Cigarette Lighter Receptacle Terminal X1 B
• S27 Head-Up Display Switch Terminal X1 5
• X85 Steering Wheel Air Bag Coil Terminal X1 6
• B80 Park Brake Switch Terminal X1 6
• S111 Night Panel Switch Terminal X1 2
10. If lower than the specified range, test the circuit for a short to ground. If the circuits test normal, replace the appropriate switch.
11. Test for less than 5 Ω between harness connector K9 Body Control Module terminal 8 X2 and the appropriate switch terminal listed below:
• S30 Headlamp Switch Terminal X1 7
• S48C Multifunction Switch 1 - Instrument Panel Terminal X1 2 (Base)
• S48C Multifunction Switch 1 - Instrument Panel Terminal X1 X1 10 (Uplevel)
• S48D Multifunction Switch 2 - Instrument Panel Terminal X1 10
• E32 Cigarette Lighter Receptacle Terminal X1 B
• S27 Head-Up Display Switch Terminal X1 5
• X85 Steering Wheel Air Bag Coil Terminal X1 6
• B80 Park Brake Switch Terminal X1 6
• S111 Night Panel Switch Terminal X1 3
12. If greater than the specified range, test the circuit for a for open/high resistance. If the circuits test normal, replace the appropriate switch.
13. If all circuits test normal, replace the K9 Body Control Module.
 Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


• Front Floor Console Multifunction Switch Replacement

• Steering Wheel Inflatable Restraint Module Coil Replacement

• Parking Brake Actuator Switch Replacement

• Control Module References for information on BCM replacement, setup, and programming