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Old 03-17-2024, 10:39 AM   #1
busmania
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Default Horn relay sparks/install question

All new wiring (Rhode Island wiring). everything works as it should...maybe. The last item of business is mounting the horn relay (horn is NOT hooked up yet). When the car is on (but not running) and I go to mount the relay on the inner fender, it sparks ever so slightly. Should it? Is this supposed to have a rubber bushing or anything? It concerns me and I don't want to burn up my new wiring by ignoring this.

Thanks!
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Old 03-17-2024, 11:10 AM   #2
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Default Re: Horn relay sparks/install question

The relay grounds against the frame rail. I typically place an external tooth lock washer between the relay and frame to assure a good ground. If you place an insulator between the relay and frame, the hors won't operate.
One of the wires going to the relay is hot. You state you have the "car" on when you attempt to install the relay. Um, why?
Shut the "car" off and then install the relay.
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Old 03-17-2024, 11:28 AM   #3
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Default Re: Horn relay sparks/install question

There should be no draw until you push the horn button, which supplies the ground to activate the primary circuit. You may have a frayed horn wire in your steering shaft tube.
There also may be a grounding at the terminals on the relay itself. This was an issue back in the day, which was addressed with a modification in manufacturing design. If your terminals are bent even slightly, they may touch the relay body, causing a short. This condition, if present, will be visible for correction.
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Old 03-17-2024, 11:33 AM   #4
busmania
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Default Re: Horn relay sparks/install question

Quote:
Originally Posted by Kube View Post
The relay grounds against the frame rail. I typically place an external tooth lock washer between the relay and frame to assure a good ground. If you place an insulator between the relay and frame, the hors won't operate.
One of the wires going to the relay is hot. You state you have the "car" on when you attempt to install the relay. Um, why?
Shut the "car" off and then install the relay.
Well, I wasn't sure where to mount it so now it got pushed off to being the last item on the electrical list and here I am. It touched the inner fender and I saw the spark which is what lead to this thread. There was no original when I got the car. Where is the original mount? On the frame or on the inner fender?

The horn is not hooked up yet (wire from the steering column is not hooked up) as I don't have a horn to hook up (yet).
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Old 03-17-2024, 11:44 AM   #5
deuce_roadster
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Default Re: Horn relay sparks/install question

With the car (ignition switch) ON and the car not running you may very well burn up your coil
and or points depending on how the points landed when you shut the car off. Skip Haney can fix that coil for you.
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Old 03-17-2024, 12:42 PM   #6
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Default Re: Horn relay sparks/install question

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Quote:
Originally Posted by ford38v8 View Post
There should be no draw until you push the horn button, which supplies the ground to activate the primary circuit. You may have a frayed horn wire in your steering shaft tube.
There also may be a grounding at the terminals on the relay itself. This was an issue back in the day, which was addressed with a modification in manufacturing design. If your terminals are bent even slightly, they may touch the relay body, causing a short. This condition, if present, will be visible for correction.
ALL good points....
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Old 03-17-2024, 02:09 PM   #7
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Default Re: Horn relay sparks/install question

Yes. Thank you. Car was only in “on” as I tested things while putting wiring together. It’s still running top notch (but still waiting to do first test drive around the block…small details take time!)
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Old 03-17-2024, 05:43 PM   #8
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Default Re: Horn relay sparks/install question

If the relay isn't connected to steering column or the horn and the only connection is the power wire and it sparks when touched to the fender panel, something isn't right with the relay.
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