Hello and welcome to Just answer.com, Super mechanic here. About your vehicle.
It sounds like the horn switch or the slilp ring in the steering column is bad if they had a switch mounted on the dash. You will want to check to see it the black wire is being grounded, (at the bottom of the steering column) when the horn pad is pushed.
Normally, when you test it with a 12v test light, (from ground) it will activate the relay and the horn will sound.
Also, the fuse is in the under hood fuse box.
Here is a diagram of the horn circuit that will help you to find the problem.
Let me see what I have on that. Remember this is a pay site, thanks
The horn relay is in the convenience center located under the instrument panel and on the left side of the steering column.