TOPIC: Testing/wiring a 1965 Sparton horn - not working

Hi all.

I have a Sparton horn in my 1965 Starcraft Arrow and I can't get it to work. It previously worked, but the crappy patch-worked wiring has been diced up as part of a new steering/motor installation -- so I need to rewire. I am now re-wiring from scratch for lights and horn (there's nothing else in that little boat anyway).

Starting with temporary straight runs to validate the devices and my logic. I removed the questionable momentary switch and associated wiring, and tried to get the horn running with a direct battery connection to validate the wiring before moving on the switch.

There's two wires coming from the horn. One from a lug inside the horn (presumed positive), and one from the outside that runs from a chassis location (presumed ground). When I wired directly to the battery, I got some struggled noises and sizzling on the positive batter connector. That suggests a short. I get continuity between the two wires from the horn, which initially puzzled me because it suggests that the horn is internally shorted, but then I realized that I may be getting continuity through the device per normal. So I rethunk it all, made some adjustments, and tried again. No sound, but a sizzling connection. So it's definitely not right.

Removed the horn, disassembled the obvious bits, cleaned it, and verified the connections. Dumped out 3 acorns which were presumably being stored for winter. Reassemble... Now I I have no idea how to test it, or to force it to make a noise. Do I need a load resistor or relay on the positive side between the battery and the horn? I'm hoping I didn't fry it.

The plan for wiring, BTW, is to run fresh (and fused) pos/neg wires from the battery to the dash, and use a +-terminal block and neg-terminal block (ground bus). Then I'll run short wires from the blocks to the switches and load devices and fuse each on the + side. For the horn, I'm putting in a new but vintage momentary to interrupt on the + wire.

Thanks for any help.

you have a picture of this horn

cap-n billybob wrote: you have a picture of this horn

Yep. Here you go. I am getting about 0.9 Ohms across the two wires, so I'm thinking that's good. It's riveted so I don't want to have to open it because I assume I need to drill out the rivets. I think the star-like screw is the pitch control.

When this type of thing happens to me, if I can't fix it, I get out a hammer I call The Big Hurt and REALLY fix it...for good! Your horn is no showpiece. Why not just buy another one? They don't cost all that much.

Nautilus wrote: When this type of thing happens to me, if I can't fix it, I get out a hammer I call The Big Hurt and REALLY fix it...for good! Your horn is no showpiece. Why not just buy another one? They don't cost all that much.

I totally get that, but I want to understand how it works too. It worked before being disconnected, so I am assuming it still works but I'm not wiring or testing it right. I could go get a replacement, but might find out that that there's nothing wrong with the horns, and it's ME that was faulty all along. Won't be the first time. I'd prefer a positive diagnosis that it's faulty.

I spent part of today diagnosing a trailer light fault. It never gets any easier.

Hello Squirrel Murphy,

Your .9 ohm reading is probably OK. Not a dead short.

I would test by connecting the hot lead though a fuse and a momentary switch. Connect to a battery and push the switch on.
If the fuse does not blow you should be able to get it to sound by slowly adjusting the star screw.

I also have a Sparton horn although it is not a sealed unit. And I occasionally pull the cover to adjust for maximum TOOT.


Thanks,
Terry

Terrydi wrote: Hello Squirrel Murphy,
Your .9 ohm reading is probably OK. Not a dead short.

Thanks Terry. That's what I needed to hear. I'll test as you suggest and report back here. Ordering a new momentary now.

Still weird to me that a simple battery loop through the horn caused sizzling (and maybe some tiny sparking). But maybe in my testing I wasn't wired the way I thought I was...