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I have an 86 as well. At one time my horn would not work. If I played and played with the horn button I might get a chirp out of it. I took mine to the dealer. They said it gets it's ground through the turn signal on the steering column. They replaced the turn signal and I have had a horn ever since.
This might not be your problem at all but it solved my problem.
I had the same problem on my 86 and it turned out to the the fuse. The horn fuse is behind the message center. You can remove the message console with out taking the odometer console. Just loosen the right side of the odometer console and you can slip out the message console. Replace all fuses. Hope this helps.