I have a 1999 W210 wagon, and I think essentially the same problem as noted above. Where, exactly, is the little belt that powers the aux. fans? Or more importantly, where is it supposed to be? I think mine broke and is totally missing. Is it in the big plastic housing where the fans sit? Do you have to take it apart to replace the belt?

Can someone describe the process a bit?

As always, I appreciate all the help I get here. I hope to be able to help others someday.