Wiper burnout?
 

Today, as I drove my 83 300SD to work, the wipers suddenly stopped in mid-wipe and the cabin started to fill with a progressively stronger burning smell. No noticeable smoke, but by the time I got to the office, it was really strong.
It was a snowy and icy morning here, and I did a pretty good job of clearing it all (ok, I could've done better), and they seemed to work good until they quit. It's very stinky and I wonder if you have any ideas on what's up here. Thanks in advance!