Mike:
Been there; done that^6. The switch overheats and deforms. The contacts
get out of alignment. I heated them (the contacts) with a soldering iron
and forced them back into alignment. The source of the problem is :
A: Bearings in fan losing lubrication causing excessive current draw;
and/ or
B: The wire carrying current supply to the switch is underrated ,size
wise. 
I rectified both and have not had any more problems.

Good Luck
Ken Lewis
kdlewis@juno.com
86 VW crewcab 
85 VW Vanagon GL
60 356 coupe

My front fan control switch in my newly purchased 85 westy is jammed in
the third speed position and the fan does not work. If I jiggled the
switch the fan would come once in a while. The heat and defrost is fairly
ineefective without the fan  specially in this frosty part of NH.
Anyadvice would be appreciated.

Mike