Horn goes on by itself

My horn occasionally goes on by itself - unfortunately that is usually in the middle of the night - I'm guessing it's caused by condensation. It's been an interesting experience meeting my neighbours at that time of the night while I jiggle the steering wheel to dislodge the circuit. Disconnecting the battery every night is just a temporary solution to let the neighbourhood sleep. My mechanic can't locate the source of the problem. He can't see any obvious wiring problem and says it could be the horn button, the relay, or the horn itself. Any ideas on how to fix this nuisance without letting the shop spend hours and hours and hours on troubleshooting?

do you use your horn at all. sure we all like to honk at assholes when they cut us off, but if you can really live without that and just flip em off, then just take off the horn "cover off the steering wheel. its just a few screws in the back of the steering wheel, and just disconnect the wires.

try another horn. junk yard or new they are cheap enough