Don't even try to replace the horns yourself. (The horns themselves aren't causing this problem anyway). The horns are behind the right headlamp housing. To remove them you have to pull the 4" diameter horns out through a 3" diameter hole!
There is a Body Computer involved with the horn system, but there is a better suspect. The computer is what runs the horn for the alarm and Remote Keyless Entry system.
There is a relay for the horns, but I can't remember if it's in the fuse box under the dash or the one under the hood. Removing it will stop the horn from sounding. The best suspect is a clock spring that's coming apart. That is a wound-up ribbon cable in a plastic housing under the steering wheel. If that cable starts to unravel, multiple circuits could short together that might do the same thing as when pressing the horn button. Unfortunately there's no easy or fast way to test it. The best clue is if the horn turns on intermittently when you rotate the steering wheel.
The next step is more involved. You can simply replace the clock spring as a test, ... If you have another one handy, otherwise you can just unplug it, then drive the car long enough to determine if the problem has stopped acting up. The air bag is on a separate circuit so that won't be affected. The plug you're after affects the cruise control, horn, and radio controls if you have them.
If that ribbon cable is coming apart, it's just a matter of time before the cruise control will not turn on and the Air Bag light will turn on.
Monday, December 21st, 2015 AT 5:02 PM