It can be a number of things, but it sounds like it's most likely either a short in the wiring, or a blown circuit.
Whether you can fix both problems depends on your skill level, but a short in the wiring is worse than a blown circuit.
If you don't know how to fix the wiring in your vehicle, take it to a shop. If it's a short, then your more likely to start developing more problems (including more shorts).
If it's a blown circuit, then that's actually not that bad. You can fix a blown circuit just as easy as putting together a couple of Lego's.
Not sure how to fix circuits? Look online (google is probably your best bet), or look through your vehicle's user manual.
***CAUTION: DO NOT try to fix wiring by yourself if you have no experience!!! Take it to the shop!!!
ALSO, DO NOT try to replace a blown circuit while your vehicle is turned on!***
(If you already knew this, do not feel that I'm insulting you. Understand that not everyone in the world knows how to do things properly and that I'm telling this for your own personal safety.)
