GM Service Manual Online
For 1990-2009 cars only

Power Windows System Components

The power windows system consists of the following components:

    • Driver door module (DDM) -- GMLAN device that receives and transmits messages and signals for window functionality
    • Passenger front door module (PDM) -- GMLAN device that receives and transmits messages and signals for window functionality
    • Left rear door module (LRDM) -- GMLAN device that receives and transmits messages and signals for window functionality
    • Right rear door module (RRDM) -- GMLAN device that receives and transmits messages and signals for window functionality
    • Driver door switch assembly (DDSA) -- GMLAN device that contains the driver, front passenger, RR and LR window and window lockout switches
    • Right front power window switch -- provides switched ground window switch signals to the PDM for the front passenger window
    • Left rear power window switch -- provides switched ground window switch signals to the LRDM for the left rear passenger window
    • Right rear power window switch -- provides switched ground window switch signals to the RRDM for the right rear passenger window
    • Left front power window motor -- contains position sensors and a module that receives signals from the DDM and provides a status signal to the DDM
    • Right front power window motor -- contains position sensors and a module that receives signals from the PDM and provides a status signal to the PDM
    • Left rear power window motor -- contains position sensors and a module that receives signals from the LRDM and provides a status signal to the LRDM
    • Right rear power window motor -- contains position sensors and a module that receives signals from the RRDM and provides a status signal to the RRDM
    • DRIVER DR MOD fuse (10-amp)
    • FRT PASS DR MOD fuse (15-amp)
    • REAR DR MOD fuse (10 amp)
    • Power Window Motors Circuit Breaker (30-amp)

Power Window Controls

The driver power window can be controlled by the driver window switch located on the DDSA. The passenger windows can be controlled by the power window switches located on the DDSA or from the power window switch mounted locally on its associated door.

The power windows can be controlled in the following modes:

    • Up
    • Down
    • Express Up
    • Express Down

Power Windows Operation

Each door is equipped with a power window motor that contains its own module. Each power window motor receives a hot at all times battery supply voltage and constant ground source. When a window switch on the DDSA is activated to the up or down position, the DDSA will interpret the signal and send a GMLAN message to the appropriate door module. Upon receipt of the message, the door module will send a voltage signal to the window motor module on the appropriate window motor signal circuit. The window motor module will then supply battery voltage and ground to the window motor to drive the window motor up or down.

When a power window is activated from a passenger door switch, the operation is the same as described above except, the window motor signal circuits are connected directly to the associated door module

Window Express Up and Down Operation

The express feature allows the windows to be fully opened or closed by momentarily pressing the window switch to the second detent of the up or down position. Due to safety concerns with express up functionality, the system is designed to detect objects that become trapped between the window glass and window frame and reverse the direction of the window. This includes the use of window motor position sensors in the motor that determine the window position. Before the express functionality may be used, the window motor must be initialized. This requires operating the power window to the full up and full down positions so the window motor module can learn the positions of the up stop, down stop and the distance in between. The window module will then report this status to the door module through the power window status circuit. For further information on window initialization, refer to Window Motor Programming - Express Function .

When the window switch is activated to an express up or down position, the door module will first receive the up or down signal and then the express signal is received. The door module will then apply voltage to the power window up or down signal circuit and then apply voltage to the apposing power window motor signal circuit. This will tell the window motor module that an express function has been requested. The window motor module will then supply battery voltage and ground to the motor to drive the window to the full up or down position.

Window Lockout Feature

The window lockout switch is part of the DDSA. The lockout function is used to prevent the passenger door windows from being operated from their locally mounted switches. When the lockout switch is pressed momentarily, the switch contacts are briefly closed, the LED indicator on the switch button is illuminated, and the DDSA processes the switch signal. The DDSA sends the switch status via GMLAN serial data to the passenger door modules. The passenger door modules then prohibit the windows from being operated from the locally mounted passenger door window switches. When the lockout function has been activated, the passenger door windows can still be operated from the driver door by using the window switches built into the DDSA. the front passenger window can be personalized to operate when the window lockout function is active.