If the wipers are working normally in all other modes other than the spray mode - perhaps the switch / stalk may be defective.  However it is very strange that the switch should fail suddenly and it is too much of a coincidence....  

Since I don't have any other explanations that come to mind, you might check the electrical connections at the switch / stalk and the body control module (passenger side kick panel) just to eliminate a 'bad connection' possibility.

'Sometimes' - a reflash of the software at the dealership will clear up some strange symptoms such as this....

Let us know what you find.

Ken

Yesterday I unclogged & adjusted windshield washer spray nozzles on my 2006 Mini cooper s and now wipers don't automatically move when I spray windshield. I have all other wiper functions except this one. I also cleaned rear sprayer as well and no issue w/ it.