I bought a 1983 240D today, it has a new AC system put in (new everything) at a cost of about $950 last year. New compressor on 134, new ducts, new condenser, etc.

It worked today, and then it cut out. I noticed that when it was working, the AUX Fan was spinning but now, the AC blows only warm-to-hot air and the AUX Fan in the very front, right behind the grill no longer spins. Since the AUX Fan is right in front of the condenser, I think this might have something to do with the AC problem.

What are things to check about why the fan is no longer running?