Bentley seems to think there is a single, dual
function switch.  Most of the
> other posters think so, too.  I'm going to head out
and take a closer look.
> Maybe even take some stuff off the engine!

the vw diagnosis book i've got says that the 1985
models were when the dual switches disappeared and the
single switch appeared ... only trouble was, it was
DURING the 1985 model year. so some 1985's will have
TWO switches and others (made later in the year) will
have only the one switch. :(