1995 Toyota Corolla HORN

Have someone depress horn button, while you put finger on horn relay. If you feel the horn relay click, then horn is problem.

This could be as simple as a bad ground, as horn grounds to chassis.

If relay is OK, remove horn and hook up to battery voltage, + to connector and - to horn frame.
If horn works and relay is OK, then clean the ground to chassis and you should be OK.

If horn relay does not click when horn button is depressed, it is either fuse/relay or the horn switch.