Do both of them do it? or just one?
If its just one, it could be a motor or something that is catching the window.
If its both, you're probably looking at a wiring or circuit problem.
It's time to bring out the multimeter and wiring diagrams my friend...
------------------
"The Yellowjacket"
Ricer 1: What the heck was that!?
Ricer 2: I don't know. It looked kind of like a yellow SN95 Mustang.
Ricer 1: Nah, fast SN95 Mustangs don't exist... Must have been a mirage or something...