I dug in and checked the blower and it is fine. I oiled the bearings while i was there. One of the resistor coils was bent too close to the bimetalic switch. I bent it away and now all is fine.
Thanks for your help sbourg.
Side note: the blower resistors are available separately if the parts guy is willing to look through all the footnotes. it costs ~$200 so i was lucky that mine was repairable.
1982 300D Turbo