Not really crazy about those cheap looking ahoog horns, I bought a 12 volt Sparton repop model A horn a few years ago. Now I'm finally ready to use it and I'm not smart enough to figure a way to wire it. Any one help?
Horn itself: Originals have terminals for hot and ground wires. Repro likely has a hot wire only and grounds at its mounting. Stocker had hot wire permanently hot, grounded through horn ****on. Modern practice is horn grounded to ch***is, hot wire to relay, battery wire on relay permanently hot, ground wire on relay grounded by horn****on. So, what wiring or terminals does the horn show, what do you have as horn ****on?
I don't find anything that looks like a place to put a terminal. There is a copper colored spring thing with a screw in the middle of it but it will not back out to put a terminal on. There is a groove under the copper piece pictured, does a bullit terminal go under that? Starter ****on for horn ****on.
That horn doesn't look too bad for a repro. The terminal block takes bullet type connectors one in each end. Don't ask me which is which as far as polarity. It can go either way but will rotate a different direction. Try it one way and see how well it works then try it the other way. I would stick with the way it works the best if you can tell. They had a yellow wire off the genrator cut out and a blue with yellow tracer to the light switch housing on the steering sector.
From memory, the original type connector is a strip maybe 1/2"X1" with a hump at each end...a bullet connector goes under each hump. My memory has that strip horizontal, or parallel to diaphragm...it would not show in that picture...can you get more pics?
I have continuity across both ends of that copper colored strip that I suppose the bullet terminals go under. I have a good ground to the base according to my multimeter.
If that is correct, you should be able to bolt it on and then run only the hot circuit via a relay... The stock double terminal onb original A-B horns mystified me on the first one I had, and I ended up removing one lead and grounding it. Seems like the terminal pockets beneath the strip ARE isolated from each other, but I couldn't look last night...all my horns seem to have migrated to the other garage. Probably can look tonight to see original horn hookup.
5window was kind enough to fax me wiring instructions. Thanks to him and all you other HAMers, this is how its suppose to be.
OK--I doped it out last night with circuit checker and Model B Sparton. The bar where stock wires connect does not have actual continuity...the two clips are separate parts, sitting on a stack of insulators and separated/retained by a rivet with insulation. The continuity you get with the test light is the motor...isolate either brush by sliding in a piece of plastic and continuity disappears; also, you can see it flicker if you just rotate the motor. This is what I failed to figgerout on my first Sparton, when I was about 14. The horn cost $20 back about early sixties, a HUGE amount of money (the deuce it was for cost $75!) and only attainable through a generous Grandmother... I could not decode that continuity then, and on that horn I detached one lead and ran it as a separated lead...presumably never noticing I still had the continuity. I was too sophisticated to just plug it in without checking, and not sophisticated enough to understand what I found. So, just plug the wires into that bar of clips and it'll go. Just in case this is utterly wrong, put the video on U-Tube...I love watching fires!
The only DC motors that will reverse rotation by reversing polarity are ones with a permanent magnet field. These horns have wound fields so the polarity does not matter it will turn the same direction no matter which way it is connected.
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