Chevrolet Silverado / GMC Sierra. Service manual — part 2480

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

The ignition is 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.

Reference Information

Schematic Reference

Interior Lights Dimming Schematics

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

Instrument Panel Lamps
Dimming Control

B2652 00

B2652 00

B2652 00

-

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

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 and park lamps ON, vary the headlamp and panel 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 harness connector at the affected component.

2. Ignition OFF, verify that a test lamp illuminates between the listed ground circuit terminal

and battery voltage.

Headlamp Switch terminal 8

Sunroof switch terminal 5

Front door lock switch w/o AN3 terminal B

Driver window switch w/o AN3 terminal A X2

Front passenger window switch w/o AN3 terminal F

OSRVM switch w/o AN3 terminal G

Transfer case shift control switch terminal 6

Roof beacon switch terminal 1

Sliding rear window switch terminal D

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Rear window switch terminal F

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.

Headlamp Switch terminal 7

Sunroof switch terminal 3

Front door lock switch w/o AN3 terminal A

Driver window switch w/o AN3 terminal 1 X1

Front passenger window switch w/o AN3 terminal B

OSRVM switch w/o AN3 terminal E

Transfer case shift control switch terminal 5

Roof beacon switch terminal 2

Sliding rear window switch terminal E

Rear window switch terminal B

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 affected component.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Refer to the appropriate replacement procedure for the component causing the condition.

Control Module References for BCM replacement, setup, and programming

DTC B3445

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

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

DTC B3445 00

Stop Lamp Circuit

Diagnostic Fault Information

Circuit/System Description

When the brake pedal is applied, the brake pedal switch normally closed contact signal circuit
voltage is interrupted to the body control module (BCM). The BCM then applies a voltage to the
stop lamp supply voltage circuit to the stop lamps.

Conditions for Running the DTC

The ignition is ON.

The stop lamps must be commanded ON.

Conditions for Setting the DTC

The BCM detects a short to ground in the stop lamp supply voltage circuit when the stop lamps
are commanded ON.

Action Taken When the DTC Sets

The stop lamps do not illuminate.

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.

Reference Information

Schematic Reference

Exterior Lights Schematics

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

Stop Lamp Supply Voltage

B3445 00

1

2

-

1. Stop Lamps Inoperative

2. Stop Lamps Always On

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Lighting - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado