Sounds like you've got a short somewhere in the circuit. I had a similiar problem with my old Celica.
I had bought it used and someone had put a wrong-amperage fuse (too high, like 10 in a 15 amp or something) in the horn/hazard/radio socket. I didn't think anything of it at the time.
It eventually blew so I replaced it with the same amp fuse that was in there. Then that one blew. So I put one more in there and the wiring started to smoke. I yanked the fuse out and ran for the fire extinguisher.
What had happened was that the horns were rusted out (low to the ground under the front bumper, on road-salted Vermont roads). The replacement of the wrong amperage fuse zorched all the wires in the front end of the car - cost me about $300 worth of rewiring work.
Moral of the story: 1) use the right amperage fuse, don't cheat and put a higher one in there, 2) if it blows, there's a good reason it did, 3) find the short....
LQ
I gotta get this fixed and get it sold so I can buy my midlife crisis Bug!
;-)
It's never blown a fuse since we bought it new...and we got the appropriate fuse according to the manual. It's something...just gotta find out what it is.