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Old 03-26-2021, 03:31 PM   #1
Slowmotoring
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Default Horn Shorted. rebuild or repair??

Looks like something inside my ahooga horn has shorted out. The horn still works but my battery died, so i tracked down the amp draw to the horn and sure enough the internals of the horn are pretty warm and has that terrible hot electrical smell! Doesn’t seem to be a dead short because my fuse didnt blow. Shows on the amp meter as a 8 amp draw. Anyone have any ideas on what to check?
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Old 03-26-2021, 06:34 PM   #2
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Default Re: Horn Shorted. rebuild or repair??

Most likely there is a short within the horn motor such as a grounded field or armature. It may be time to have it checked out and rewound as necessary by one of the horn experts. One or two have been named and given good references on this site.

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Old 03-26-2021, 06:53 PM   #3
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Default Re: Horn Shorted. rebuild or repair??

Thats what im afraid of. Windings look like they got pretty hot...
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Old 03-26-2021, 07:08 PM   #4
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Default Re: Horn Shorted. rebuild or repair??

I tried doing a search to find someone who can rebuild the horn and i had no luck. Does anyone know of anyone that does this?
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Old 03-26-2021, 08:07 PM   #5
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Default Re: Horn Shorted. rebuild or repair??

Look in the Stickey: Model A/AA Ford Websites...Can YOU add to the list?" found at the top of the main page for vendors.

Last edited by Y-Blockhead; 03-26-2021 at 11:20 PM.
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Old 03-26-2021, 09:50 PM   #6
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Default Re: Horn Shorted. rebuild or repair??

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Don’t forget to check the wiring in the horn rod in the steering wheel. It’s possible a poor connection is causing a problem. That turned out to be the problem with the horn on my A recently. BTW - my horn draws 6-8 amps, and it is very loud.

Good luck - Jim
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Old 03-27-2021, 09:19 AM   #7
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Default Re: Horn Shorted. rebuild or repair??

Could be two problems at once - horn wire shorted to ground, and armature stuck. If so, oil the wicks to get it to spin freely, then hook it up again to see if it sounds all the time.
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Old 03-27-2021, 10:09 AM   #8
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Default Re: Horn Shorted. rebuild or repair??

Slip some plastic/paper under brushes, if still draw its the field windings
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Old 03-27-2021, 11:01 AM   #9
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Default Re: Horn Shorted. rebuild or repair??

Investigated the horn some more this morning. I found that with the horn cover off i had no amp draw. Cover on loose=no amp draw. Tighten cover=amp draw. I was able to make the amp draw come and go by turning the cover mounting screw tighter and looser to the point i know exactly where it will start to short out. Havent figured out what is getting shorted out yet but it is getting narrowed down.
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Old 03-27-2021, 12:07 PM   #10
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Default Re: Horn Shorted. rebuild or repair??

The cover screw is to long and touching the brush holder, fairly common.
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Old 03-27-2021, 04:07 PM   #11
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Default Re: Horn Shorted. rebuild or repair??

https://www.macsautoparts.com/model-...hoCnIsQAvD_BwE

Proper screw has a shank so it won't squeeze the cover too tight.
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Old 03-27-2021, 04:29 PM   #12
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Default Re: Horn Shorted. rebuild or repair??

My horn didn’t go so well. I don’t really enjoy mechanical work so I removed it and took it to an auto lec. He returned it and said he had repaired it but it still didn’t work. I think he tested it with a 12v battery. I took it apart only to find it shorting because the hot wire had earthed. I insulated it with heat shrink. Problem solved. The auto lec is not really a liar but I figured he just didn’t want small jobs otherwise he doesn’t want to work for gary.

Some time back I needed a home sensor light modified so I asked my friend who lives not too far away if he would do it. Yes of course he responded. As he was doing this job I asked, you are an electrical engineer aren’t you. No he replied, a mechanical engineer. I asked myself well there is any reason that I, who is not qualified can’t do it. So I did. Installations, modifications and repairs. I did buy a $10 tell tail to check for electricity prior to putting my fingers near wires. The difference between myself and tradesmen is the cost of labour.
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Old 03-27-2021, 08:13 PM   #13
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Default Re: Horn Shorted. rebuild or repair??

Thanks for the info! Once again the people of this site have been extremely helpful!
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Old 03-28-2021, 08:20 AM   #14
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Default Re: Horn Shorted. rebuild or repair??

The vendors stock a 'special' screw that is only threaded part way so that the screw can not be turned in too far that it shorts out the horn.

https://www.brattons.com/horn-cover-screw.html
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Old 03-28-2021, 03:37 PM   #15
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Default Re: Horn Shorted. rebuild or repair??

Make sure your horn cover, where the screw goes in, is flat and has not pulled the cover in too far.
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