I have a 2009 SmartCar and it decided a few days ago that its rear wiper was not going to stop wiping. No amount of fiddling with the controls stops it. Anyone have any ideas?
Pull the fuse.
“Snap off the wiper arm” is probably not the answer you’re looking for.
I feel your pain though. My wife got a Ford C-Max earlier this summer and I still haven’t figured out how to work the wipers. Every once in a while I will accidentally turn on the rear wiper and can’t figure out how to turn it off (or how I even managed to turn it on in the first place).
Say “Wiper, stop wiping!” three times.
It works for Dora.
Sorry, I have nothing real to suggest.
Just be careful of what else that fuse does. (rear lights???) It may be better to disconnect the wire at the base of the wiper, if it’s easy to get at.
Only drive when it rains.
I had a Porsche 924 back in the '80s that would decide to turn on the intermittent wipers for no apparent reason.
Pulling the fuse was my solution.
Alright. This is funny. 
I’d like think perhaps a faulty relay.
Open your relay panel and look for one labelled accordingly.
“OK, I’ve got the cover off and I’m looking at the relays, but can’t find one marked “faulty”, now what?”
He clearly said to look for the one labeled “accordingly”, not one marked “faulty”. Geez.