2003 ml350 within a week of each other both of my passenger window mechanism went south on this car. Drivers side, removed panel to find a broken plastic pulley that belongs toward the bottom of center post in door. It has a cable that runs around it and back up top threw the window motor. Passenger side I havnt taken apart yet. but thought I heart parts fall down the door well when wife tried to actuate the window. Any one know of a failure common like this or otherwise? How about a breakdown of interior door parts? Thanks to any and all advice. Darrell

 

most of the time the weld on the window regulator will break. the arms will move but the glass wont. also the window switch packs go ba. but usually just the driver switch.