B2652

DTC B2652

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (with HP2) (Initial Inspection and Diagnostic Overview)Diagnostic System Check - Vehicle (without HP2) (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 B2652 00
- Passenger Compartment Dimming 3

Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) applies a 12-volt reference voltage through the headlamp and panel dimmer switch 12-volt reference circuit to the headlamp and panel dimmer switch. When the dimming switch is placed in the desired position, the dimmed voltage setting is applied from the headlamp and panel dimmer switch through the instrument panel (I/P) lamp dimming switch signal circuit to the BCM. The BCM then applies the dimmed voltage to the I/P lamp dimming control circuit and the components on the circuit.

Conditions for Running the DTC

* Battery voltage must be between 9-16 volts.
* The ignition must be ON.

Conditions for Setting the DTC

The BCM receives an open, voltage, or ground signal on the I/P lamp dimming control circuit.

Action Taken When the DTC Sets

The I/P lamps are not illuminated.

Conditions for Clearing the DTC

* The conditions for setting the DTC are no longer present.
* A history DTC clears after 100 malfunction-free ignition cycles.
* The BCM receives the clear code command from the scan tool.

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 appropriate component.
2. Ignition OFF, verify that a test lamp illuminates between the listed ground circuit terminal and B+.

* Rear window switch terminal F
* Headlamp switch terminal 8
* Transfer case shift control switch terminal 6
* Sunroof switch terminal 5
* Folding seat switch terminal 4
* Power liftgate open/close switch terminal C
* CJ3 HVAC control module terminal 2

• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

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

* Rear window switch terminal B
* Headlamp switch terminal 7
* Transfer case shift control switch terminal 5
* Sunroof switch terminal 3
* Folding seat switch terminal 5
* Power liftgate open/close switch terminal B
* CJ3 HVAC control module terminal 1

4. Command the Dimming Test high to low with a scan tool. The test lamp should turn from bright to dim when changing between the commanded states.

• If the test lamp is always OFF, test the control circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the BCM.
• If the test lamp is always bright, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.

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

Repair Instructions

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

* Headlamp Switch Replacement (Cadillac) (Service and Repair)Headlamp Switch Replacement (Except Cadillac) (Service and Repair)
* Rear Side Door Window Switch Replacement (Rear Side Door Window Switch Replacement)
* Sunroof Switch Replacement (Service and Repair)
* Rear Seat Recliner Switch Replacement - Overhead Console (Rear Seat Recliner Switch Replacement - Overhead Console)
* Rear Seat Recliner Switch Replacement - Lock Pillar Trim (Rear Seat Recliner Switch Replacement - Lock Pillar Trim)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming