I have a 1999 Honda Accord LX with 80,000 miles. When the temperature drops at night, the horn will stick on and blow continually. I took the car to the local dealership and they took apart the steering wheel, but were unable to locate any problem. I was told that there is no way to adjust the horn contacts away from the air bag/wheel cover on this model. I did a goggle search and found a similar issue with a 1998 Accord, but with no concrete answers as to a fix. There is no alarm on this car and the problem only started with the arrival of cool nights here in Northern California (the car was in Florida previously). Have any of you guys in the northern environs ever come across anything like this? My sleep deprived neighbors and I would greatly appreciate any advice you might offer.

 

that's a strange one .... the only thing that I can think of is that the relay is getting squeezed from contraction due to the weather making contact and energizing the horn. You could install another relay in line so that the horn is only available when the car is on, but that bypasses rather than fixes the problem. Pull out the horn relay to see if it appears deformed or cracked. Other than that, I'm drawing a blank.

 

Take it to another dealer. Sounds like the one you took it to must be incompetent.