B2652

DTC B2652

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 B2652 00
- Passenger Compartment Dimming 3 Circuit

Diagnostic Fault Information






Circuit/System Description

The body control module (BCM) supplies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage from the CHMSL/BCK-UP fuse through the instrument panel lamp supply voltage circuit illuminating the components listed below:

* Headlamp switch
* Instrument panel cluster (IPC)
* Driver and passenger window switches
* Driver and passenger door lock switches
* Outside rearview mirror switch

Conditions for Running the DTC

* The ignition is ON.
* The headlamps or park lamps ON.

Conditions for Setting the DTC

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

Action Taken When the DTC Sets

The BCM does not attempt to illuminate the instrument panel lamps.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Circuit/System Verification

Ignition ON, park lamps ON, adjust the dimmer switch from dim to full bright. The I/P lamps should dim and then become full bright.

Circuit/System Testing

1. Ignition OFF, disconnect the X2 harness connector at the BCM.
2. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.

^ If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

3. Ignition OFF, connect the X2 harness connector at the BCM.
4. Disconnect all of the instrument panel lamp components fed by the BCM instrument panel lamp control circuits listed below.

* Terminal 3 X2

- Headlamp Switch
- Instrument Panel Cluster (IPC)

* Terminal 3 X6

- Driver Window Switch
- Driver Door Lock Switch
- Outside Rearview Mirror Switch
- Passenger Window Switch
- Passenger Door Lock Switch

5. Ignition ON, clear the DTC with a scan tool.
6. Operate the system within the Conditions for Running the DTC and verify the DTC does not reset.

^ If the DTC resets, test the control circuits for a short to ground. If the circuits test normal, replace the BCM.

7. Reconnect each component one at a time and verify that the DTC does not reset as current.

^ If the DTC resets as current, test or replace the component responsible for setting the DTC.

8. If all circuits test normal, replace the BCM.

Repair Instructions

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

* Headlamp Switch Replacement (Impala)
* Instrument Cluster Replacement (Impala)
* Front Side Door Window Switch Replacement (Impala)
* Door Lock Switch Replacement (Impala)
* Power Mirror Switch Replacement.