Random alarm on 06 Sebring Touring ragtop
 

A 2006 Sebring Touring convertible (70,000 miles) I inherited from the original owner has a randomly occurring problem; the horn starts blowing at random.
An ASE certified mechanic said it was the (factory) alarm system. He doesn't work on alarm problems.
I have stopped it by beating on the horn button on the steering wheel, but the problem recurs.
What's the best way to troubleshoot this? I am not healthy, nor am I mechanically gifted.
I'd like to know if there's any way to gather more info before going to another mechanic or a dealership.
Thank you in advance.

On mine it was the horn pad below the airbag cover. Is 2 thin contacts badly kept apart . Over time they get to touch and make the horn blow.
There is a video on youtube about taking the airbag out to repair the pad with a thin stripe of duct tape.