How do you fix a horn in a 1989 Mazda B2200 pick-up truck?

Mazda truck horn.

First thing is to locate where the problem is by removing the wire on the horn and attaching a test light to the wire. Ground the test light and have someone push the horn button. If the light comes on, you have either a problem in the horn, or the horn is not grounded. If the light does not come on, the fault is either in the horn button (switch) or in the wiring.

Ed