Theory Of Operation
WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.
The window switches have three positions which are neutral, up and down. When pressed in the up or down position they send a signal, or command, to the Body Control Module (BCM) respectively. When pressed, the switch provides 12 volts from the Window Switch Supply circuit through a 350.0 Ohm resistor (built in) to the Up or Down signal circuit. The Window Switch Supply circuit also supplies 12 volts for switch illumination