Driver Power Window Operation
WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
The switch for the driver power window has three positions UP, Down and Express Down and its position is a direct input into the DDM. Upon receiving a request for power window operation (switch activation), the DDM 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.