I was a plonker. Had a bike rack on the rear windscreen and instead of reaching to the left stalk to operate my fog lamps in the dank gloom of an Aberdeenshire morning, I twisted the right stalk.

The wiper goes up about 5" then rams into the bike rack when it stops. Of course I am in moving heavy traffic so no chance of jumping out to hurriedly pull out bike rack. When I eventuall stop 20 mins later. Remove bike rack and the wiper (following a nudge) continues its unimpeded sweep, however when it gets to the same "place" again it sticks. With a gentle nudge it continues its travel, so the motor and park switch are good.
Is it likely I have stripped a gear? Anyone had this and resolved it?
Cheers
Alan