I have a 1995 Buick LeSabre. From time to time the horn blows on its own, with no one in the vehicle. The last occurence I was unable to open the doors or trunk or unlock the vehicle, either with the remote or manually. Unfortunately this occurred at 2AM and I did not think to use the key, so I don’t know if the key would work. I ended up breaking a vent window and touching the horn rim with a 4ft. level. Any one have any ideas?
I had the same problem on a 1971 Ford Maverick and my brother had the same problem on a 1977 Cadillac. In both cases, it turned out to be the horn switch on the steering wheel.