I have a 1997 S10 pickup truck.
In late January I hauled it on a front-end car trailer (sorry, don’t know the techical term) from Chicago to Texas. Yes, I did get the drive-shaft disconnected before I left 
Anyway, I got about 200 miles before I pulled into a gas station and the horn was going off!! It was really embarassing and I ended up pulling fuses until it stopped. Keep in mind the car was off with the drive shaft disconnected.
When I got to Texas I had the drive shaft reconnected and just left the fuse out since I was broke.
So now I want to leave Texas and I want to sell the truck. Unfortunately, the horn doesn’t work and thus it won’t pass the inspection and thus no one will want it even though it’s priced stinking cheap.
Today I thought I might as well try the simpliest thing and just went ahead and put the fuse back in. Nothing happened. The interior lights came on. Horn wouldn’t work.
Ok, that sucks.
Well, I happened to be outside and all of the sudden about 15 minutes later… HORN. Nonstop. I ran and got my keys and pulled the fuse again.
I am on a super-strict budget so I would like to know if this might be something i could fix myself cheaply??
I’m thinking about just selling the damn thing for $100 less than I originally wanted hoping that someone will snatch it up anyway… but I’m worried since who wants an old car that might not be able to be registered??
Look under the hood for a plastic box containing fuses and relays. The top, or underside of the fuse/relay box lid should show which one is the horn relay. One of the other relays is usually the same type. You could swap another of the relays to see if the horn now works. Here’s a picture of the relay: http://www.autozone.com/N,15701286/shopping/partTypeResultSet.htm