Just purchased a 1997 MB S420 sedan last week. Last night, I used the windshield washer system which also activated the headlamp wipers since the lights were on. Problem: one of the headlight wipers is stuck (opposite its normal resting position) over to the side and will not move; the wiper on the other side is also stuck (opposite its normal resting position0 and it sounds like a motor is running on this side anytime the headlamps are turned on....Any ideas on a fix???