Windshield Wipers Occasionally Not Working
 

1989 560SEL, 96k miles. Windshield wipers (ww's) occasionally will not work, like when it's raining. I'll switch the ww's on, they will work for a while, then freeze. They will not move no matter what position the switch is in. Or, they will be working, I'll turn them off for a while, when I try to turn them back on they will not work. If they are not working, I park my car, come back to it later, and the ww's start working again. Very Intermittent. Where to start, where to start? Thanks, Scott

Scott,
Replace the ww fuse. Doing this solved a similiar problem in my '82 240D. We only find out if the ww don't work when it's raining cause we RARELY use them when it's not raining.
hope this solves the problem.