First locate the fuse box under the hood, in front of the battery. Then use a pair of needle noise plyiers to pull the ten amp fuse out. Get your new fuse place it in slot and make sure you press it in firmly.
The horn fuse is the same as the stop lamp fuse
The fuse for the horn should be on the drivers side underneath the dash. There is a diagram on it that shows the horn fuse.
check the fuse
Then you have a short in the wiring, the horn button is defective, or the horn itself is defective.
Fuse? check your fuse box for the fuse indicated "horn" remove and replace if neccessary. if fuse is not the problem, check wiring to horn under the hood in the engine compartment.
The horn relay should be located on the fuse box under the dash. most of the horn relay's that I have seen are a big white fuse, if it isn't on the fuse box, check near the horn.
It is important to know where the parts are within a car. The horn relay in a 1993 Mazda Protege is found in the cars fuse box.
The horn is 6-8" to the left of the hood latch assembly. It's held by a single bolt on the painted frame and is hidden behind the front bumper.
check the fuse to make sure it has not blown out
the horn relay is in the fuse box under the hood (just south east of the battery) the horn relay is the top right block. underneath the fuse box hood there is a chart labeling everything for you
The owners manual should have a fuse box diagram. If you don't have one, try MOTORLIT.COM
We have a 1995 Miata and the horn stops working from time to time. If you lift the hood, right in front of the radiator, the horn plugs in. I just re plug it when it happens. I hope this is what your miata is doing.