GM Service Manual Online
For 1990-2009 cars only

Power Window System Components

The power window system consists of the following components:

    • Door lock/windowswitch
    • Window control module
    • Left rear window switch
    • Right rear window switch
    • Window regulator motors in each of the doors
    • WNDW MTR Circuit Breaker 20A
    • WNDW CNTRL Fuse 2A

Front Window Operation and the Master Control Window Switches

When the ignition switch is in the RUN or ACCY position, or retained accessory power (RAP) is enabled, battery positive voltage is supplied to the door lock/window switch. When the left front or right front window switch is pressed in the down position, a signal is sent to the window control module which supplies voltage to the appropriate window motor down circuit and ground to the window motor up circuit causing the window to open. When the left front or right front window switch is pulled in the up position, a signal is sent to the window control module which reverses the polarity of the window motor and the window closes.

Express Down Feature

The driver and passenger windows will travel to the fully down position when the left front or right front window switch is pressed and released. Pulling the same window switch to the up position will cancel the express down command.

Express Up Feature

Some models are equipped with smart motors which allows for express down and express up functions. When the left front or right front window switch is pulled and released, the appropriate front window will travel to the fully up position. Pressing the same window switch to the down position will cancel the express up command. As a safety feature, the smart motors will detect excessive resistance while performing the express up function and automatically reverse direction to prevent injury to any occupants that may become trapped between the closing window and the door frame. The automatic reverse safety feature can be overridden by pulling and holding the window switch.

Lockout Switch Feature

The door lock/window switch contains a rear window lockout switch which disconnects the battery positive voltage supply to the rear door window switches, disabling them. Normal rear window operation is still available from the door lock/window switch.

Rear Window Operation and the Rear Window Switches

The rear power window door switches receive battery voltage through the window lockout control circuit if the rear window switches are enabled. Ground for the rear passenger power window motors is supplied through normally closed up and down contacts of both the rear window switches and the switches on the door lock/window switch. When the either rear window 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 rear window motor. Since the other side of the rear power motor is connected to ground through the normally closed up contacts of both the rear window switch and door lock/window switch, the window travels down. By placing the rear window switch in the up position, the polarity of the power window motor is reversed and the window travels up.