I just got asked what would cause the horn to blow in a 2006 F350? I mean constantly, as in pull the fuse to make it quit. I was told it happened in the middle of the night in front of the house. Pretty weird. My search only revealed references to train horns, Dodge Big Horns, etc. Nothing to with stuck horns.

 

Theft deterrent go off? Had this happen to my old gasser ( 92 gmc stepside ). Someone broke into it and they tried to jimmy the key. They failed but they set off the theft deterrent and horn was stuck. Found the wire for the horn was messed up. Just disconnected it.

 

I've heard of the clock spring inside the wheel breaking and causing it to honk when someone takes a turn or something... weird.

I'm trying to jog my memory, but I seem to think I've read about this before, guys having their alarms going off in the middle of the night and stuff.

Does he happen to have an aftermarket alarm on there? Or a remote start?