rain sensing wipers go off on ignition
In addition, my wipers come on sometimes on a perfectly clear sunny afternoon for no reason. Usually only a single wipe, but have had two, three or even more wipes. Once I had to just turn them off completely.
Best advice I can give is ignore the single wipe in the morning at startup, and clean the glass real thoroughly in the area of the sensor.
I did get caught once in a sudden deluge on the freeway and noticed that it was a little slower than I would have been jumping to max speed.






