correct me if im wrong (i usually am
) but arent the wiper positions controlled by motor?
i remember hearing on car talk a long time ago that there is (and i could be remembering wrong) a motor to turn them on and a motor to turn them off / stop them and return them to their position.
a woman was complaining that her chevy's wiper blades often stopped in the middle of the windshield.. if memory serves me, they said to put in a new motor.
just a helpful / potentially unhelpful tip.