GM Service Manual Online
For 1990-2009 cars only

Power Windows System Components

The power window system consists of the following components:

    • Driver window switch
    • Passenger window switch
    • LR window switch (Crew Cab)
    • RR window switch (Crew Cab)
    • Up relays in each of the window switches
    • Down relays in each of the window switches
    • Window motors in each of the doors
    • PWR/WINDOW 30A Fuse

Power Windows System Controls

The power windows system can be controlled by pressing or pulling the appropriate power window switch.

Driver Window Operation

The driver window switch is supplied battery voltage through 30A fuse in the underhood fuse block. The driver window switch UP and DOWN relays controls power and ground to the window motor through the motor control circuits. The driver window switch relays can be energized by the integrated rocker switch. While the driver window switch is in an inactive state, both of the window motor control circuits are grounded through the UP and DOWN relays. When an UP or DOWN relay is energized, the battery supply circuit is closed to the corresponding motor control circuit while the other control circuit remains grounded through the de-energized relay. The supply side of the UP and DOWN relays receives voltage through the PWR/WINDOW fuse.

Crew Cab

The rear passenger power windows can also be operated from the driver window switch master control which provides a low reference for the UP and DOWN relays. The rear passenger window switches on the driver master control have 2 positions; UP and DOWN, their position is a direct input into the driver window switch.

Express Down Feature

The drivers window has an express-down feature that allows the window to be lowered fully without continuously holding the switch. Pressing the front of the switch past the first position will activate the express-down mode. The express-down mode can be canceled at any time by pulling up on the switch.

Lockout Switch Feature

The window lockout switch, when closed, provides power to the passenger door switches enabling normal window operation and when the lockout switch is open, power is cut to the passenger door switches disabling window operation. Normal window operation is still available from the driver master control.

Passenger Window Operation

The passenger power window switches are supplied battery voltage through 30A fuse in the underhood fuse block. The door window switch UP and DOWN relays controls power and ground to the window motors through the motor control circuits. The window switch relays can be energized by the integrated rocker switch. While a window switch is in an inactive state, both of the window motor control circuits are grounded through the UP and DOWN relays. When an UP or DOWN relay is energized the battery supply circuit is closed to the corresponding motor control circuit while the other control circuit remains grounded through the de-energized relay. The supply side of the UP and DOWN relays receives voltage through the PWR/WINDOW fuse.