Rain-X windshield washer fluid
Went to the dealer and they said that the sensor inside the reservoir is defective and that ingredients in Rain-X windshield washer fluid tends to muck up the sensor rendering it completely disabled.
I've used Rain-X winshield washer fluid for years in all sorts of cars (VWs', Audis', Porsches', Saabs') and never had any problems.
Any of you guys ever heard of this?


