Chevrolet Silverado / GMC Sierra. Service manual — part 2967

6. Test for more than 10 volts on the signal circuit terminal C while commanding the rear

window DOWN with a scan tool.

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

7. Test for more than 10 volts on the signal circuit terminal A while commanding the rear

window UP with a scan tool.

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

8. Ignition OFF, connect harness connector at the rear window switch and disconnect the

harness connector at the rear window motor

9. Test for less than 1 ohm between the control circuit terminal A and ground

If greater than the specified range, test the control circuit for a short to voltage or an
open/high resistance. If the circuit tests normal, replace the rear window switch.

10. Test for less than 1 ohm between the control circuit terminal B and ground

If greater than the specified range, test the control circuit for a short to voltage or an
open/high resistance. If the circuit tests normal, replace the rear window switch.

11. Connect a test lamp between control circuit terminal A and control circuit terminal B.

12. Ignition ON, command the rear window UP and DOWN by using the rear window switch.

The test lamp should illuminate when commanding the UP and DOWN states.

If the test lamp is always OFF during either of the commands, test either control circuit
for a short to ground. If the circuits test normal, replace the rear window switch.

13. If all circuits test normal, test or replace the rear window motor.

Component Testing

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

2. Install a 25-amp fused jumper wire between the control terminal A and 12 volts.

Momentarily install a jumper wire between the control terminal B and ground. The window
motor should perform the UP or DOWN function.

If the function does not perform as specified, replace the window motor.

3. Reverse the jumper wires; the appropriate window motor should perform the DOWN or UP

function.

If the function does not perform as specified, replace the window motor

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

2008 Chevrolet Silverado 1500

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

Sierra & Silverado

Rear Side Door Window Regulator Motor Replacement (Extended Cab) or Rear
Side Door Window Regulator Motor Replacement (Crew Cab)

Front Side Door Window Regulator Motor Replacement

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

Control Module References for DDS, PDS and BCM replacement, setup and
programming

POWER WINDOWS MALFUNCTION (A31 W/O AN3, DL3)

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

Driver Window Switch B+

1

1

-

-

Passenger Window Switch B+

2

2

-

-

Left Rear Window Switch B+

3

3

-

-

Right Rear Window Switch
B+

4

4

-

-

Left Rear Window Down
Signal

3

3

3

-

Left Rear Window Up Signal

3

3

3

-

Passenger Window Down
Signal

2

2

2

-

Passenger Window Up Signal

2

2

2

-

Right Rear Window Down
Signal

4

4

4

-

Right Rear Window Up Signal

4

4

4

-

Window Master Switch
Lockout Control

3, 4

3, 4

3, 4

-

Driver Window Motor
Control

1

1

1

-

2008 Chevrolet Silverado 1500

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

Sierra & Silverado

Circuit/System Description

The power window system will operate any time the ignition is in the ACC or RUN position. The
power window system will also operate whenever the body control module (BCM) is in the
retained accessory power (RAP) mode. The driver power window switch contains individual
window switches for each of the power windows. All windows may be controlled up and down
from the driver master control. The individual passenger power window switches will only
control the up and down operation of their respective power window.

Each power window contains a reversible power window motor. The direction the window
travels is dependent upon the polarity of the supply voltage. By reversing polarity of the supply
voltage the window motor will move up or down. Each power window motor is internally circuit
breaker protected.

Battery voltage is supplied to each power window switch through the accessory voltage supply
circuit. The power window switch also receives a constant ground source. The power window
motor control circuits are connected to ground through the normally closed up and down contacts
of the power window switch. When the power switch is placed in the down position, the power
window motor down control circuit is switched to 12 volts and is applied to the down side of the
power window motor. Since the other side of the power motor is connected to ground through

Passenger Window Motor
Control

2

2

2

-

Left Rear Window Motor
Control

3

3

3

-

Right Rear Window Motor
Control

4

4

4

-

Driver Window Switch
Ground

-

1

1

-

Passenger Window Switch
Ground

-

2

2

-

Left Rear Window Switch
Ground

-

3

3

-

Right Rear Window Switch
Ground

-

4

4

-

1. Driver Power Window Malfunction
2. Front Passenger Window Malfunction
3. Left Rear Power Window Malfunction
4. Right Rear Power Window Malfunction

2008 Chevrolet Silverado 1500

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

Sierra & Silverado

the normally closed contacts of the up switch, the window travels down. By placing the power
window switch in the up position, the polarity of the power window motor is reversed and the
window travels up.

Reference Information

Schematic Reference

Moveable Window Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Windows Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Circuit/System Verification

1. Ignition ON, command the each window UP and DOWN using the appropriate window

switch on the driver master control and the appropriate passenger door window switch.
Each window should perform the UP and DOWN functions from each switch.

If the front driver door window is inoperative, refer to Driver Power Window
Inoperative below.

If the front passenger door window is inoperative, refer to Passenger Power Window
Inoperative below.

If the left rear or right rear door window is inoperative, refer to Rear Power Window
Inoperative below.

2. Disable the rear door window switches by activating the window lockout switch on the

driver master control. The rear door window switches should be inoperative.

If the rear door window switches are still active, refer to Window Lockout Switch
Malfunction below.

2008 Chevrolet Silverado 1500

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

Sierra & Silverado