This happened to me once on my way back home to Sacramento (go Kings!) from Oakland. When I was in Oakland Somebody had given me one of those tiny free bibles which when wedged up against the wiper motor made the thing work normaly. The thing has plastic gears that wear away but if you tweek it a tad to one side you sometimes can get a little more life out of it. I eventually got a long (about 18") hose clamp, put one side around the steering column and put the other around the motor and tightened it to make the gears mesh enough to function. So I like to say that I once fixed my car with a bible( it is still there three years latter).