GM Service Manual Online
For 1990-2009 cars only

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 provides an overview of each diagnostic category.

DTC Descriptor

DTC B2610: Passenger Compartment Dimming 1 Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Instrument Panel Lamp Supply Voltage

B2610

2

1

--

1. Interior Backlighting Does Not Dim

2. Interior Backlighting Inoperative

Circuit/System Description

The BCM supplies a voltage reference through the I/P dimming voltage reference circuit to the interior lamp dimmer switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the I/P dimming signal circuit to the BCM. The BCM interprets this voltage signal, then applies a variable voltage through the instrument panel lamp supply voltage circuit, illuminating the components listed below:

    • Instrument Panel Cluster (IPC)
    • HVAC control module
    • Radio
    • Headlamp switch
    • Driver window switch
    • Driver door lock switch
    • Front passenger window switch
    • Front passenger door lock switch
    • Outside rearview mirror switch
    • Traction control switch
    • PRNDL lamp (console shift)
    • Driver Information Center (DIC)
    • Steering wheel controls (RPO UK3)

Conditions for Running the DTC

    • The ignition is ON
    • The headlamps or park lamps are ON

Conditions for Setting the DTC

The BCM detects a short to ground on the instrument panel lamp supply voltage circuit.

Action Taken When the DTC Sets

The BCM will not DIM or illuminate any backlighting.

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 scan tool information

Circuit/System Verification

Ignition ON, cover the ambient light sensor. Adjust the interior lamp dimming switch from dim to full bright. The backlighting lamps should dim and then become full bright.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connectors at all components fed by the instrument panel lamp supply voltage circuit.
  2. Ignition ON, clear the DTC with a scan tool.
  3. Operate the vehicle within the conditions for running the DTC and verify the DTC does not reset.
  4. If the DTC resets, test the instrument panel lamp supply voltage circuit terminal 48 at BCM for a short to ground. If the circuit tests normal, replace the BCM.
  5. Reconnect each component one at a time and verify that the DTC does not reset.
  6. If the DTC resets, test or replace the component responsible for setting the DTC.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming