FYI, according to my Haynes "VW Air-cooled Vanagon" shop manual, first
switch postition (83a) is for front fogs, second position (83b) is
front and rear.  Internal light is lit in second postion only, and,
big surprise, is called "rear fog light warning lamp."  For this light
to work, a ground wire to the switch (terminal 31) is required.
Diagram shows 8 amp fuse between switch and rear fog light (1), no
relay.  I'm certain switch should activate a relay for front fogs.
Switch power is sourced from light switch, terminal 56, meaning fogs
work with headlights on only (in factory configuration).  While switch
can certainly be "used as an on-off switch for other accessories as
well," note that the switch has the foglight icon painted on it, but I
assume that can be removed.