Windshield Wipers Wont Shut Off

I have a 1995 Buick Lesabre, 40,000 miles. Windshield Wipers will turn on, low high, mist. Will not delay or shut off. To get them to shut off, I have to turn the wipers off to the off position and then turn off the car. When I restart the car the wipers are off and go back to "hiding" under the hood.

Having the wipers going after the water has dried has scratched my windshield. Any help would be appreciated !!!