Circuit/System Description

WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.

The driver and passenger window motors supply 12 V signal circuits to their respective window switches, when a window switch has been activated, a switch closes providing a ground to the appropriate signal circuit causing the voltage to drop to 0 V. The window motor will detect the voltage drop in the signal circuit and will command the window to move in the desired direction.

The driver window master control switch also contains control switches for the passenger window functions. When a window switch is pressed, a serial data message is sent to the body control module. The body control module examines the request and checks for messages from other power window motors that may prohibit window movement. If no prohibitive messages have been received, the body control module will send a serial data message to the passenger window motor which will perform the command as requested.

The window motor monitors the voltage in the door handle switch signal circuits, when the exterior door handle is pulled, contacts within the exterior door handle will close providing a ground path for the signal circuit. Also the door latch has contacts which when the interior or exterior door handle is pulled, the contacts within the door latch will close providing a ground path for the door handle switch signal circuit. The voltage within the signal circuit will drop when either door handle is pulled, the appropriate door motor will detect the voltage drop and will lower the window approximately a 1/2 inch to prevent damage to the door window seal as the door is opened. The body control module will send a serial data message to the window motor when the door has been completely closed so that the window motor can command the window to index to the fully up position.