Thanks for the tips. I tried cleaning the buttons with some electric contact spray, but still no go. The wiring looks good and like i said the two front windows work. The only thing is that the safety button is broken, and i totally removed the switch and they still dont' work. I don't have a new switch yet b/c i'm waiting for it to come in. Perhaps that switch is causing the problem. I hear click noise from the back windows when i press the buttons, but nothing happens. i can't imagine both motors being broken. gota love mercedes and their back windows lol