Windshield Wiper on 1992 Mercedes-Benz 400E

Windshield wiper comes on without switch being turned on and goes at highest speed and will not turn off? Only stops when ignition key is turned off. However, when key is placed in ignition and engine is not turned on it works fine. I'm so disgusted with this problem. Have not read anyone else having this issue anywhere online. Please help; thanks in advance.

Asked by for the 1992 Mercedes-Benz 400E
wiper motors and switches go out on any car, even a Benz ( it's 17 years old) have a good electrical automotive diagnostic tech check your system. Best of Luck!
1 more answer
This sounds like a switch issue to me.