Does a 1986 Toyota Corolla have a horn relay problem if fuses and horn are good but it still doesn't work?

The horn should have two wires going to it. One wire is supposed to be hot (battery voltage 12v). The second wire is open but gets grounded when the horn button is depressed, thus completing the electrical circuit and making the horn toot.

So, the first check is: are you getting 12v on one of the two wires?

the second check is: when a helper presses the horn button do you get ground to the second of the two wires?

The third check is: if you ground the second wire at the horn does it toot?

If the first check does not produce 12v, then the fuse is blown or the wire from the fuse to the horn is defective.

If the second check does not ground the wire, then the wire to horn button is defective or the horn button itself is defective.

If the third check does not toot the horn, replace the horn itself.