Adding to what Jim said.

1. Check the inner door panels.  If someone tore that plastic water can
easily get inside the cabin that way.  Also check the door drains.
If the plastic is torn just buy the kit to seal house windows (plastic and
double sided tape) which is what VW told me to do.
If you have a sunroof check all 4 drains for that too!
My old '91 Passat leaked from the roof panels and it had no sunroof!  8^o

2. What Jim said.  Also see what other components are on that circuit and
not working!

3.  Battery or cables, clean and tighten all connections.  I have seen bad
cable ends that attach to the starter.  Also those cables could be a thicker
grade.  ;-)
If this is a Digifant engine, then check the ground wires at the cylinder
head and the wires to the throttle switches.  They are known to break.
Has this engine been tuned lately?  Have you checked for any vacuum leaks
too?

2) My rear wiper doesn't work. Every time I try to replace the fuse it
blows immediately.

On mine, the problem was caused by the wires fracturing where they come out
of the roof panel on the left hand side. I guess years of opening and
closing makes the wires weak?

Neil