B2610

DTC B2610

Diagnostic Instructions

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

DTC Descriptor

DTC B2610
- Passenger Compartment Dimming 1 Circuit

Circuit/System Description

The body control module (BCM) receives a variable voltage signal from the instrument panel (I/P) dimmer switch requesting to illuminate the instrument panel controls illumination lamps to a desired intensity. When this occurs, the BCM directly sends a variable voltage based on the I/P dimmer switch position through the instrument panel lamps dimming control circuit to the instrument panel controls illumination lamps

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

The instrument panel lamps dimming control circuit is shorted to voltage.

Action Taken When the DTC Sets

The instrument panel controls illumination lamps will be always on.

Conditions for Clearing the DTC

* This DTC will clear on current status after the condition for setting the fault is corrected.
* A history DTC will clear after 100 consecutive ignition cycles without a fault present.

Circuit/System Verification

Park lamps ON, operate the interior dimmer switch from bright to dim. The IP switch backlighting should illuminate from bright to dim.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at an affected component.
2. Test for less than 1 ohm of resistance between the affected component ground circuit terminal listed below and ground.

* Transfer case shift control switch terminal D
* IPC terminal A5
* HVAC control module terminal B9 X1
* Rear window wiper/washer switch terminal B
* Headlamp switch terminal C X1
* Upper right steering wheel switch terminal 5
* Upper left steering wheel switch terminal 3
* Lower left steering wheel switch terminal 4
* Lower right steering wheel switch terminal 4

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

3. Connect a test lamp between the listed control circuit terminal and ground circuit terminal.

* Transfer case shift control switch terminal C to terminal D
* IPC terminal A7 to terminal A5
* HVAC control module terminal A7 X1 to terminal B9 X1
* Rear window wiper/washer switch terminal C to terminal B
* Headlamp switch terminal B X1 to terminal C X1
* Upper right steering wheel switch terminal 3 to terminal 5
* Upper left steering wheel switch terminal 2 to terminal 3
* Lower left steering wheel switch terminal 1 to terminal 4
* Lower right steering wheel switch terminal 1 to terminal 4

4. Command the lamp dimming test 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 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 BCM.

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

Repair Instructions

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

* Transfer Case Shift Control Switch Replacement (GMC, Buick)
* Rear Window Wiper and Washer Switch Replacement
* Headlamp Switch Replacement