Horns blows once than shorts out.

[Displayman]

We have a 47 Mercury convertible.
12v system, 6v horns. The horns have worked
fine for the last couple of weeks since installing.
Now, if you blow the horn once, it blows a fuse.
We have replaced the wires form the fuse block to the horn ring.
Still shorts out. We have checked the connections to the horn itself
with a good ground. Could the horms be going bad? We don't over use
the horns at all. Does anybody have a schematic of the horn ring
assembly? All suggestions greatly appreciated.

Thanks,

Bob- Hampshire, Illinois

[Barry Wolk]

Horns are a simple electro-magnet. I would say that the draw is too high. What size fuse is blowing, and what size is the wire?

[Displayman]

10 amp fuse-new wire Ron Francis harness, I would have to check the gauge.

[Barry Wolk]

Horns can draw 20-amps, or more. I would try a separate 30-amp fuse-holder off the battery and use a 20-amp fuse. Use 10 gauge wire and you should be fine.

However, if your car does not have a horn relay you could burn up the contacts in the horn button, which simply completes the circuit to ground. A 30-amp relay should last forever.

[flathead4rd]

My six volt horns lasted about a week on 12 volts. Ten amps doesn't seem like enough for a horn circuit plus you need to run it through a relay. Just buy some aftermarket 12 volt horns.

[Barry Wolk]

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Good point. A 6-volt specific horn would draw twice the amperage at 12-volts. You might try an in-line resistor if you want to use the old horns.

[Displayman]

Thanks for the info on resistor and 20 amp fuse.

Bob

[Displayman]

20 amp fuse. works fine now.
Thanks Barry.

Bob-Hampshire,Illinois

[denverslim]

Wow! I've been running on 12 volts for close to 10 years now. Still have the old stock 6v horns. They are loud though.
I guess in the ten years though, I have honked less than a minute...slim

[Barry Wolk]

It's like electric brakes on trailers. The coils are not voltage specific but need to be controlled by a variable resistor.

You are overdriving your horns, but they should hold up, as little as you use them. If you added an inline resistor like those used with coils, the volume would return closer to normal.