Horn

[1970F100]

I have a 70' F100 Sport and Ranch Custom, 360 3MT, everything works but the horn - replaced horn, relay, switch, pad - wiring seems ok (ground is good). Drives me nuts!

[FORDification]

Did you check to make sure the spring-loaded contact is there and intact?



It gets mounted into hole number 2 in this picture:

[Mohillbilly]

Has your truck had power steering added? The steering columns are different lengths, and I have a problem sometimes getting the brush to contact properly, too.

[1970F100]

No PS - and the brush is in place.

[Mohillbilly]

My battery box is rusted out and when I first got my truck, the battery had rubbed a short in some of the wires, causing a short that kept the horn and the turn signal from working.

[71 LONG BED]

I pinched my horn wire trying to put my radiator back in and it made the horn blow! Scared the bejesus out of me!!! It was one of those small after market air horns.
The wire cover melted a little but it still works, One day I'll patch in a new wire.

[Fake Name]

Did you check to make sure the spring-loaded contact is there and intact?



I

That part has an official name:

"Horn Carbon"

one of my first lessons as a jobber parts guy, long ago. Along with how to use the those big, long binders of parts catalogs. It just ain't the same with these computer dealies today. Nope. It's much better!

fn

[1970F100]

Thanks - I'll look at the batterey tray - it's structrally ok but pretty rusty.

[jzjames]

Take one more look at that "horn carbon" and burnish the contacting surfacaes, and the clean the contacting ring on the steering wheel. When I did that, mine finally worked!

[layedout72]

yahy, just cuz it looks like metal to metal, more likely than not, its not a good contact. if anything sand then with a mid-grit paper.

[68F250]

That's one circuit I've never checked out, the horn button.

Basically it's hot all the time, looking for a ground. After going thru the button, how does it get back to ground? Does it have to go thru the bearings in the column to reach the chassis? The rag joint isolates the shaft to the steering box.

[fordman]

the spring part goes in the wheel first. the large brass end should contact the horn button.

[Supermike]

Thanks!

[seattle67]

Mike,
You may see + 12vdc there, but only if the horn relay is plugged in and the the coil in it is good. In that situation, you would be seeing the +12vdc that is going through your horn relay coil. (This would be a good thing as it means your coil is good)

What confuses some people with the horn circuit is that the +12vdc goes straight to the relay, its not switched, it's the neg 12vdc that's switched. What happens when you push on your horn button is that it contacts ground, this ground is picked up by the horn carbon and sends the ground, or - 12vdc to the horn relay. The relay is now energized, closing a contact that sends +12vdc to your horns.

I hope that makes some sense.

[Supermike]

Thanks! That helps...