GM Service Manual Online
For 1990-2009 cars only

Power Windows System Components

    • Driver Door Module (DDM)
    • Passenger Door Module (PDM)
    • LH Rear Door Module (LRDM)
    • RH Rear Door Module (RRDM)
    • Driver Door Switch Assembly (DDSA)
    • RH Front Power Window Switch
    • LH Rear Power Window Switch
    • RH Rear Power Window Switch
    • LH Front Power Window Motor
    • RH Front Power Window Motor
    • LH Rear Power Window Motor
    • RH Rear Power Window Motor
    • PWR WDO 30 Amp Circuit Breaker

Power Windows Operation

The vehicle is equipped with power windows controlled by the door modules. Each passenger door power window can be operated, either from a switch built into the driver door switch assembly (DDSA), or from a switch mounted locally on its associated door. The driver door power window can only be operated from the switch built into the DDSA.

If the driver door module (DDM) receives a window switch request from any of the window switches built into the DDSA, the DDM checks the Class 2 serial data to see if conditions are correct (i.e. ignition switch position) to permit window operation to occur. If conditions are correct, the DDM, either supplies power and ground to its associated window motor, or sends a command via the power door serial data line to the passenger door module controlling the window. The passenger door module controlling the window then supplies power and ground to its associated window motor to move the window as requested.

When one of the local window switches mounted on one of the passenger doors is operated, the associated passenger door module examines the request and checks to see if there are any messages from the DDM prohibiting the window operation. If conditions are correct, and no prohibitive messages have been received from the DDM, the associated passenger door module then supplies power and ground to its associated window motor to move the window as requested.

Windows Power and Ground

Each door module has its own seperate battery positive voltage supply circuit for power window operation, but they are all fed by the same 30 amp power window circuit breaker located in the rear fuse block. Each door module also has a seperate ground circuit for its power window operation. These circuits are in the same dedicated connector as the window motor drive circuits of each door module.

Window Motors

Each door module supplies battery positive voltage and ground, through the window motor drive circuits, to its associated window motor. The window motors are reversible. The direction the window moves depends on which motor drive circuit the battery positive voltage is applied to, and which motor drive circuit the ground is applied to. To move the window in one direction, the module applies battery positive voltage to one of the motor drive circuits, and ground to the other motor drive circuit. When a window movement in the opposite direction is needed, the module reverses the polarity and supplies power and ground to the opposite circuits to move the window in the reverse direction.

Rear Window Lockout Feature

The rear window lockout switch is built into the Driver Door Switch Assembly (DDSA). When it is pressed momentarily, the LED indicator is illuminated, and the DDSA receives the switch signal. The DDSA sends a message over the power door serial data line to the driver door module (DDM) indicating that the switch is active. The DDM then sends a message over the power door serial data line to both rear door modules prohibiting the rear windows from being operated from the rear door window switches, or, to all of the passenger door modules prohibiting any passenger window from being operated from its associated window switch. The passenger windows can still be operated from the driver door by using the passenger window switches built into the DDSA.