My windshield wipers just modified on their own, they won't turn off. I'm not sure how or where to start troubleshooting this so help is appreciated. Here are the symptoms. I don't know the names of the modes so I made some up. wipers in off position - wipers act as if they are in...

Hi All; I have an 01 540i with a difficult problem to diagnose. The windshield wiper stops working after about 30 Minutes of heavy rain. I have tried all the different settings when it stops working without any luck. If I pull over, then sometimes it starts to work after about 15 mins...