B2610

DTC B2610

Diagnostic Instructions

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

DTC Descriptor
DTC B2610 00
- Passenger Compartment Dimming 1 Circuit

Diagnostic Fault Information





Circuit/System Description

When the ignition switch is turned to the RUN position, the radio's VF displays turn ON at maximum brightness. When the park lamps are ON, all incandescent back lighting turn ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. At the same time all VF displays dim to match the indicated dimming level. The panel dimmer switch potentiometer is an input to the body control module (BCM). When the driver selects a dimming setting by moving the I/P dimming switch potentiometer, all incandescent back lighting lamps are provided with a specific voltage. The incandescent back lighting lamps are then grounded at G201, G302, and G303. When the I/P dimmer switch is moved from MIN to MAX, all vacuum fluorescent (VF) displays, as well as all incandescent back lighting respond from minimum intensity to maximum brightness in response to the I/P dimmer switch.

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.

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 (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

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

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the inoperative component.
2. Test for less than 5.0 ohms between the inoperative 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 inoperative component.

Repair Instructions

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

* Transfer Case Shift Control Switch Replacement (GMC, Buick) (Service and Repair)
* Rear Window Wiper and Washer Switch Replacement (Service and Repair)
* Headlamp Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM, HVAC control module, or IPC replacement, programming, and setup.