K, another oddball question.

I never noticed before, but the horn wiring is not on the electrical diagram in the 1956 Shop manual. On trucks with the stock dual horns, are the horns wired in parallel or in series? Does anyone have a schematic of the horn wiring diagram?

 

Vanpelt has a great series of diagrams on-line at:

http://www.vanpeltsales.com/FH_web/f...ings_links.htm

Hope it helps

 

Thanks Larry. They have the same physical routing diagram I have but not the electrical schematic.

 

Ok...The Concours Auto Parts catalog shows them hooked up in series. I'll see if I can get it scanned for you this week.

 

That would be great. Thanks for the assist.

 

Its wires in a series/parallel circuit. The horn wire from the relay goes to the right side horn and from the right horn there is a "cross over" wire to the left side horn. This wire runs under the hood latch panel in the 4 wiring loom clips on the underside along with the headlight cross over harness.

Hope this helps,
Kevin

 

Yeah Kevin, that's what I realized after I made the original bonehead post. They would have to be in parallel, otherwise, one horn would have to be insulated from the frame.

Larry, I'd still like to see that schematic, if you can swing it.


This all started when I got to tuning the horns as instructed in the shop manual. At 12V, they were drawing way too much current. A quick resistance measurement showed them to be 0.5 to 0.6 Ohms each. If I leave them on for more than 3 or 4 seconds, the internal bypass resistors start to smoke! I strongly suspect they are 6V horns that some previous owner used as replacements for the original 12V. They do work as long as you don't hold the horn button down for more than 1 or 2 seconds at a time.

I asked if they are wired in series because I was thinking that two 6V horns in series might divide the 12V between them. Then it ocurred to me that both horns have one side grounded so they can't be in series. It also ocurred to me that their current draw when operating is not DC. On my oscilloscope, it's sort of a square-wave as the internal points open and close. Two of those in series really isn't like dividing the 12V DC supply across the two, although it does sort of work.

Anybody got any original 12V horns they want to get rid of? I need one high-pitch (13832), and one low-pitch (13833).

 

Earl,

You're right about the "square wave" DC, but if you can insulate one from ground (shouldn't be difficult), you can run them in series and the total inductance works out about right. May not be perfect, but you shouldn't smoke anything & your horn relay won't stick (common problem when 6V horns pull too much current).

Besides, the 6V horns sound mean on 12V

If you do find 12V horns, I may be interested in your 6V horns

 

Hey Earl...how do I get the pictures on here?

 

Larry,

I completely missed your question in the post above and now I see it's been quite a while. Well, I'm still working on finding a couple of horns and I'd still like to see the schematic if you have it.

As far as posting pictures, check out mr4speed's step-by-step guide:

John/Andrew's Magic Picture Posting Instructions

 

Got ya...I was trying to figure out how to put the diagram in here for ya.

FYI..it shows a single wire into the relay then two wires out, one to each horn.

 

I have a Concours catalog so I scanned it:



Enjoy!

 

Hi Kevin. That's the same wire routing diagram I have. I need a schematic, though. I'm slowly learning there is a difference.

 

how did you get the diagram on th site? Looks different then the one I have which shows the relay and horn's wiring.

Thanks

 

Larry,

Click on the link entitled

"John/Andrew's Magic Picture Posting Instructions"

in my post above. The instructions there will walk you through the process of posting an image. If you have no luck doing that, just go to Earl's World (below) and click on the e-mail link at the bottom of any page. You can send me the schematic as an e-mail attachment. Thanks.