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. The DDM contains the the driver door switch (DDS) which is integrated into the module. The DDS contains the driver, front passenger, RR and LR window and window lockout switches.
    • Passenger front door module (PDM)--GMLAN device that receives and transmits messages and signals for window functionality. The PDM contains the front passenger door switch (PDS) which is integrated into the PDM. The PDS contains the front passenger window switch.
    • Left rear power window switch--Provides switched ground window switch signals to the DDM for left rear passenger window operation
    • Right rear power window switch--Provides switched ground window switch signals to the PDM for right rear passenger window operation
    • 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 DDM and provides a status signal to the DDM
    • Right rear power window motor--Contains position sensors and a module that receives signals from the PDM and provides a status signal to the PDM
    • DRIVER DR MOD fuse (15-amp)
    • PDM fuse (15-amp)
    • PWR WINDOWS Circuit Breaker (30-amp)

Power Window Controls

The driver power window is controlled by the driver window switch which also serves as the master switch for all windows. The passenger windows can be controlled by the power window switches located on the driver power window switch 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 right front or right rear passenger window switch on the DDS is activated to the up or down position, the DDM will interpret the signal and send a GMLAN serial data message to the PDM. Upon receipt of the message, the PDM will send a signal to the appropriate window motor module on the GMLIN serial data circuit. The window motor module will then supply battery voltage and ground to the window motor to drive the window motor to the up or down position.

When a left front or left rear passenger window switch on the DDS is activated to the up or down position, the DDM will interpret the signal and send a signal to the appropriate window motor module on the GMLIN serial data circuit. The window motor module will then supply battery voltage and ground to the window motor to drive the window motor to the up or down position.

The left rear power window switch receives 12 volts from the DDM and provides a signal to the DDM when the switch is activated. The left rear power window switch is permanently grounded. When the left rear power window switch is activated to the up or down position, the DDM interprets the signal and sends a signal to the left rear window motor module on the GMLIN serial data circuit. The window motor module will then supply battery voltage and ground to the window motor to drive the window motor to the up or down position.

The right rear power window switch receives 12 volts from the PDM and provides a signal to the PDM when the switch is activated. The right rear power window switch is permanently grounded. When the right rear power window switch is activated to the up or down position, the PDM interprets the signal and sends a signal to the right rear window motor module on the GMLIN serial data circuit. The window motor module will then supply battery voltage and ground to the window motor to drive the window motor to the up or down position.

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 each motor that determine the window position.

When a window switch is activated to an express up or down position, the door module associated with the power window switch will first receive the up or down signal and then the express signal is received. The door module will then send a signal over the GMLIN serial data circuit to the appropriate power window motor. 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 master DDS. 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 DDM processes the switch signal. The DDM sends the switch status via GMLAN serial data to the PDM. Both the DDM and PDM will prohibit the passenger windows from being operated from there locally mounted window switches. When the lockout function has been activated, the passenger door windows can still be operated from the driver door by using the DDS.