Power Windows Description and Operation

Power Windows Description and Operation

Power Window System Components

The power window system consists of the following components:

* Driver Door Switch (DDS)
* Passenger Door Switch (PDS)
* Body Control Module (BCM)
* Rear door power window switches
* Power window motors in each of the doors (circuit breaker protected)

Power Window System Controls

The power window system will operate anytime the retained accessory power (RAP) system is active or when the ignition switch is in the ACCY or ON position.

The driver and passenger door lock and side window switches are integrated control module switch assemblies. The driver door switch (DDS) driver and front passenger window switches are normally open, 3 position rocker type switches, with detents for up, down, and express down. The DDS rear passenger window switches are normally open, 2 position rocker type switches, with detents for up and down. The DDS rear window lockout switch is a push button type switch that provides an active signal to the DDS whenever pressed. Whenever the rear window lockout switch is pressed the DDS will activate or deactivate the rear window lockout function depending on the current state, and illuminate the switch indicator whenever the function is active.

The passenger door switch (PDS) contains a single power window switch that is an integral component. Closing of this normally open, rocker switch provides the PDS with a request for the front passenger power window operation. The switch for the front passenger window has 3 positions Up, Down and Express Down. Each of these switch positions is a direct input to the PDS.

The rear passenger door power window switches are normally open, 2 position rocker type switches, with detents for up and down. Each switch incorporates up and down window motor relays that can be energized by the rocker switch or through body control module (BCM) control circuits.

Driver Power Window Operation

The switch for the driver power window has 3 positions Up, Down and Express Down and its position is a direct input into the driver door switch (DDS). Upon receiving a request for power window operation (switch activation), the DDS supplies voltage to the power window motor left front up or down circuit and grounds the opposite and the power window motor runs to move the window up or down.

Front Passenger Power Window Operation

The switch for the front passenger power window has 3 positions Up, Down and Express Down, and its position is a direct input into the passenger door switch (PDS). Upon receiving a request for power window operation (switch activation), the PDS supplies voltage to the power window motor right front up or down circuit and grounds the opposite and the power window motor runs to drive the window up or down.

The front passenger power window can also be operated from the driver door switch (DDS). The front passenger window switch on the DDS has 3 positions Up, Down and Express Down and its position is a direct input into the DDS. Upon receiving a request for front passenger power window operation, the DDS transmits a GMLAN message indicating the changed switch position. When the PDS receives this message, the PDS supplies voltage to the power window motor right front up or down circuit and grounds the opposite and the power window motor runs to move the window up or down.

Rear Passenger Power Window Operation

The rear passenger power window switches are supplied battery voltage through 25A circuit breakers in the IP fuse panel. The rear door window switch up and down relays control power and ground to the window motors through the motor control circuits. The rear window switch relays can be energized by the integrated rocker switch or by the body control module (BCM) through the up and down signal circuits. While a rear 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 BCM supplies the rocker switches with accessory/retained accessory power (RAP) voltage through the lockout control circuit while the lockout function is inactive. The supply side of all the window up and down relays receive voltage through the battery voltage supply circuit and the lt door or rt door circuit breakers respectively.

The rear passenger power windows can also be operated from the driver door switch (DDS) through a GMLAN message to the BCM. The rear passenger window switches on the DDS have 2 positions Up and Down their position is a direct input into the DDS. When the BCM receives a command to operate a rear window up or down the appropriate signal circuit is used to energize the up or down relay in the rear door window switch.

Rear Power Window Lockout Operation

NOTE: Power window lockout switch disables REAR passenger window switches only and has no effect on the operation of the FRONT passenger window switch.

The rear window lockout function is operated from the driver door switch (DDS) through a GMLAN message to the body control module (BCM). When the BCM receives an active lockout command, the rear door power window switches are disabled. The lockout control circuit from the BCM supplies the accessory/retained accessory power (RAP) voltage to the rear window switches while the lockout function is inactive and removes the supply voltage to activate the function. Once activated, the lockout feature will remain in effect until the ignition switch is cycled or the DDS receives another power window lockout switch activation.