Hello, I have a 2001 f350 and the horn has never worked in it, I always assumed it was the clockspring because the air bag light was on and the cruise control also didn't work. But I recently did a dash swap from a 2008 F350, and rewired the clockspring wiring and new steering wheel and all, and The horn still doesn't work and also my cruise doesn't work(also the truck has a rear differential from a 2008 f350 so i'm not sure if that could be the issue) as soon as the battery cables touch battery the horn is going off, So i removed the fuse under dash. I don't believe its the steering wheel horn pad. I tried replacing the relay in fuse box assuming maybe it was stuck open. But then after i changed the horn relay, the lights on my switches(headlight switch, Auxiliary switches, heated seats, bla bla) (circuit 19) are staying lit after truck is off and door is locked. I have not checked any wiring under the hood but the truck has had a few owners before me that have done shady wiring jobs, but everything in the cab has been redone by me. I'm not sure if it could be some type of alarm or something (VSM) but it seems the relay is getting constant power and is somehow tapped into circuit 19(dash switch lights) I've looked at a few horn wiring diagrams but none have helped so far.

I accidentally deleted the I/P relay box under dash when doing the swap because the blinker relay is no longer used, but it also includes your fuel pump relay and one other relay that i'm not sure what it does, Im suspicious of the green/yellow wire going to that unknown relay, because the horn was not getting constant power when i had that box off but when I fixed it, it starting going off.

Hoping anyone has some type of wiring diagram or any advice on where to go next, I am planning to search under the hood pretty soon on the horn wiring but for now the issue is unknown.

Thanks so much for any help!

 

Here are some diagrams for the horn.

 

really appreciate those diagrams! We’ll see if i can figure the issue out.