Is the switch you are looking for the one where the thermostat is inside
the 3 speed fan switch? If so I could not find a switch either but I
found a workaround that worked for me. If your thermostat is OK then you
can buy a fan switch from the non westy AC and just pull the wires off
the old switch and change them to the new switch. The configuration of
the switch is identical. Now you will have to drill a new hole in your
dash and switchpanel because you will have independent switches for the
fan and the thermostat. If your thermostat is shot you will have to buy
that switch as well but I think you can just pull the wires off your old
one. The VW dealers have both the independant switches and also the
knobs which you will need as well. A sign shop could make a new panel
for you if you want the job to look finished.

Tony 85GL "Westfailure"