Horn blows when sitting still

You would need to check for a short in the wiring between the steering wheel and horn relay. Since the ground wire starts from behind the air bag I strongly recommend you take it into a shop for proper diagnostic. What you can do for now is remove fuse number thirteen to keep the horn from coming on.

The automatic truck light was flashing, would the make the horn blow? What about the alarm on it would that have something to do with it?

Is it your alarm that is setting off or is it the horn staying constantly on?