Chevrolet Silverado / GMC Sierra. Manual — part 2963

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, command the rear windows UP and DOWN by using the window switches on the
driver master control and their respective rear window switches. The rear windows should
perform the UP and DOWN function from each switch.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate rear window switch.

2. Ignition ON, with the rear window switches enabled, test for more than 10 volts between

the control circuit terminal D and ground.

If less than the specified range, test the control circuit for a short to ground or
open/high resistance. If the circuit tests normal, replace the BCM

3. If all circuits test normal, replace the rear window switch.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Rear Side Door Window Switch Replacement (Crew Cab) or Rear Side Door
Window Switch Replacement (Extended Cab)

Control Module References for BCM replacement, setup and programming

SYMPTOMS - FIXED AND MOVEABLE WINDOWS

1. Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in

order to verify that all of the following are true:

There are no DTCs set.

The control modules can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions.

Refer to the following system descriptions:

Power Windows Description and Operation

IMPORTANT: The following steps must be completed before using the symptom

tables.

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Fixed and Moveable Windows - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Rear Window Defogger Description and Operation

Visual/Physical Inspection

Inspect for aftermarket devices which could affect the operation of the system. Refer to
Checking Aftermarket Accessories .

Inspect the easily accessible or visible system components for obvious damage or conditions
which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to
Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the
symptom:

Rear Window Defogger Malfunction

Power Windows Malfunction (A31/AN3/DL3) or Power Windows Malfunction (A31
w/o AN3, DL3)

Power Rear Sliding Window Malfunction

REAR WINDOW DEFOGGER MALFUNCTION

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.

Diagnostic Fault Information

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

Relay Switch B+

2

2

-

-

Rear Defog Relay Control

B0283 06

B0283 06

2

-

Rear Defog Relay Ground

-

B0283 06

2

-

Rear Defogger Control

2

2

1

-

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Fixed and Moveable Windows - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Circuit/System Description

When the rear defogger button is pressed, voltage is supplied to the relay coil by the HVAC
control module which also illuminates the rear window defogger indicator. B+ voltage is
supplied at all times to the relay switched input and the relay coil is always grounded. This allows
battery positive voltage from the relay switched input through the switch contacts and out the
relay switched output to the rear window defogger. Ground for the rear defogger grid is provided
by G304 or G307.

Reference Information

Schematic Reference

Defogger Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Rear Window Defogger 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

Rear Window Defogger Grid
Ground

-

2

2

-

1. Rear Defogger Always On
2. Rear Defogger Inoperative

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Fixed and Moveable Windows - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado