My heating fan is working

Could be a number of things really. If all the fuses are fine, it pretty much isolates it to the system itself, which has switches, relays, resistors, and motors. All of which could be bad. If you still have the warranty I'd take it to a VW or Audi dealership. If not, you're going to have to isolate the problem. Does AC only work? Does it work only on floor heat or only on dash heat? Check every switch position possible and see which, if any come on. From there you're gonna need a voltmeter and patience.....