“I was washing the windshield on my 87 300E and I raised the single-arm wiper to the up position and now I can't get it back down.”

Same exact thing happened to me today on my C230. Tons of dried salt spray/road grime had it jammed pretty good. I got back to the office (quite embarrassing with the wiper sticking out) and grabbed the spray Pam from our kitchen. I think it was the latch that catches the arm from rising up too high. The Pam did the trick nicely and did not leave too much to clean up.

__________________
Michael

1988 300 SL (5 Speed)
1994 E320 Wagon
1997 C230