Passenger side wiper stopped working. It's not frozen in place...moves freely when the car is shut off. Are Prius wipers similar to other cars...single electric motor with control arms? Or some other type of mechanical control?
Single motor with linked arms. The motor itself is on the passenger side so my best guess is that the serrations in the wiper arm are no longer gripping the serrations on the pivot. I'd initially try tightening down the wiper arm - the specified torque is 21 N·m/15 lb·ft. If that doesn't help, take it off, clean the arm serration (manual says with a round file, but I would have thought that would remove the serration!) and clean the pivot with a wire brush, then reinstall, again using the torque specified above.
One thing to watch for is leaving the wipers turned on, and then shutting the car off. The next time that you get in and start the car, the wipers will automatically start. If the car has been parked outside in winter weather, and the wipers get iced/frozen to the windshield, then sometimes they may not break free on their own when they automatically start, and the drive spline(s) will be stripped as the wiper motor attempts to move the frozen wipers. I had this happen to me several years back on a Chevrolet. Once in a while I still manage to forget to turn them off prior to stopping the car (easy to do when wipers are set on "intermittent").
