All major circuits are protected from overloading or short circuiting by fuses. A 12 position fusebox is located beneath the dashboard near the steering column, or located in the luggage compartment on some air conditioned models.
When a fuse blows, the cause should be investigated. Never install a fuse of a larger capacity than specified, and never use foil, a bolt or a nail in place of a fuse. Make sure to always carry a few spares in case of an emergency. There are 8 amp (white) fuses and 16 amp (red) fuses in a typical VW fusebox. To replace a fuse, pry off the clear plastic cover for the fusebox and depress a contact at either end of the subject fuse.