David,

The switch fits in the spare slot to the right of the tach.  The fog light
switch kit contains the switch, bulb, and bulb socket.  This is VW part
number ZVW 123 251.  The kit is hard to find, but I think you can find the
individual parts easier.  I believe that these are the individual part
numbers, but I could be mistaken:

251 941 535 - Fog Light Switch, Lighted
141 957 397A - Bulb Socket
N17751-2 - Bulb

Steve
89 Westy