Wipers failed during a trip to TN last weekend. First time using the wipers in high speed, during sudden torrential downpour on the interstate. The passenger side blade suddenly dropped out of sight, whacking the front grill as the other wiper kept moving. Then the other shifted enough so that it was dropping a couple inches below the windshield. Found the passenger wiper arm completely free wheeling - acting like a gear had stripped. After getting under the hood found that a pushrod for that wiper had popped off, and the C-clip normally retaining it missing. Found the driver motor mount loose. Got a C-clip and re-attached the pushrod, enough to resume travel - and of course it quit raining right after that...
A single motor drives both wiper arms. That C-clip is a potential recurring failure point, so I'll be looking into something more substantial for the long haul.