Hmmm... hear me out.
In my U13 Bluebird, I had a problem with the indicators coming on for no reason and oneday there was a puff of smoke... Made me worried and thought I would need a new indicator stalk. After finding out it was not too expensive to replace, I decided to have a go at fixing it. (If I stuffed it up it wouldn't cost heaps).
I pulled out the stalk and pryed open the little tab dealies to open it and found that in one place a bit of plastic that sat between 2 copper terminals had worn out from all the use and was making the switch terminals touch when they shouldn't. Was also a little melted. Sooooo... I got a cable tie and jammed it in the gap cut it off and super glued it in place. Never had a problem since... I suggest you pull out the wiper stalk, open it up and see what you can see. They seem to be a similar design to the Blubey's. You never know.
Good luck.