Don't worry about it Rose. Some trucks do this and no one really has an explanation for it other than the way the buttons are wired in. When I was chasing my cruise control issue I discovered by truck does the same thing (sounds horn by pressing certain cruise buttons at the same time).

I ripped my steering column apart, checked all the wiring, buttons, clock spring, etc. and found no issues. Found and fixed my cruise issue at the clutch switch by finally hooking a scanner up to it. My truck still sounds the horn if I push those buttons, and according to the link above, it's been doing so since 2008 with no other negative consequences or failures.

And for the record, your 2003 doesn't have a GEM so that's not it. They switched to a VSM in 02 and mounted it in a different location than the GEM.

 

I reported this back a year ago too with no ill affects, just wierd when I did it..

 

Its normal. The buttons on the wheel each have a certain resistance to them that the PCM looks for to control the cruise or horn. It just so happens that those two buttons together are close enough to the horn's value that it'll go off when you push them.

 

Chris-

Would love to hear some speculation on what could cause the horn to sound without it running/driving/pressing switch. Since you've been into one I thought maybe you might speculate. I love speculation.

 

Good info. I wasn't aware of the change in 02 to the VSM from the GEM. Thanks.

 

In '02 there were quite a few electrical changes for the SuperDuty's.

 

Chaffed wires, water or corrosion in the buttons or clockspring connectors, problems with the GEM, or if it's a resistance thing like Trevor talked about, who knows. Seems like most of the stories we hear about a horn by itself either happen when it's been raining, or when it's 3AM.

Have you tried pushing buttons when it sounds to make it stop?

 

No. I didn't know about the connection to the cruise control until I pulled the relay and then found out the next time I tried C.C.

No water has ever been a problem, so I think I'll just dig into it at some point. Duck Fan and Stewart_H are gonna be over next Sat so maybe I'll hit it then.

Thanks Chris!

 

Yep, doesn't change a thing. As long as ON and COAST are pressed, she beeps

 

Sorry for the confusion John. My last comment was directed at Andy and his problem since your issue is normal and nothing to worry about.

 

So....strange coincedence or what...but my girlfriends 99 F150 does the same thing, ON+COAST = HORN

 

It is normal, My 02 does it and so does My wife's 09 escape. I had a 99 f150 and it done it also. I would not concern Yourself with it.

 

My '02 F-350 does the same thing. I never would have tried it, but I read this thread and while I was sitting in my truck today had to give in to curiousity. Sure enough, horn goes off. Isn't modern technology grand? lol

 

I agree Clock Spring !!

 

My early 99 CA truck never did that... Hmm.