The simplest way to successfully troubleshoot a short of this  nature is to
simply unplug disconnect everything from the circuit  and  start hooking
things back up.  When you plug in the offensive item and the short is
reintroduced, the breaker/fuse will open again.  Then you will know what
caused it.   It is possible to have a cumulative effect short. Where several
things are drawing slightly more than they should.  But that won't be the
case in a circuit as simple as this one.
Good luck with it, I hope this helps you.
  Jeff/Florida

The 20 amp fuse for the front/dash fan in my 1990 Westfalia blows every time
I turn the fan on.  My guess is a short somewhere.  Anyone have any
experience or words of wisdom with regard to troubleshooting this problem?

Thanks.

TJK
--
Todd J. Kaderabek