Horn circuit advice
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Junior User
Joined: Nov 2006
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Horn circuit advice
Last week I rebuilt the horn activating assembly inside the steering wheel and until last night, the one horn (passenger side) worked fine. Not content with something that worked great, I installed the second horn (a new "high sound" replacement) and connected it to the wire coming out of the wiring harness where the horn should have been mounted. So far so good. When I turned the ignition, and hit the button, the horn sounded once, then stopped.
According to my shop manual, there is no fuse for the horn, just a horn relay. Has anyone else had this problem? Is it possible I have blown the relay? I also am not sure I have positively identified the relay itself. There is a rubber coated small (maybe 3/4" x 3/4" x 2") doo dad mounted at the top of the radiator housing, on the engine side opposite the driver side horn. Is that the relay?
Any assistance would be appreciated.
According to my shop manual, there is no fuse for the horn, just a horn relay. Has anyone else had this problem? Is it possible I have blown the relay? I also am not sure I have positively identified the relay itself. There is a rubber coated small (maybe 3/4" x 3/4" x 2") doo dad mounted at the top of the radiator housing, on the engine side opposite the driver side horn. Is that the relay?
Any assistance would be appreciated.
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
John,There is an issue with grounding that sometimes comes into play. Tis my understanding that the horn circuit is always hot, and mashing the button/ring grounds it out, so I'm not sure what role the switch plays.
I had to add a ground wire on my column to go around the rag joint. There is a factory ground in there that can go bad. Once I put the jumper on the column my horn blows loud everytime. For what it's worth.
John
I had to add a ground wire on my column to go around the rag joint. There is a factory ground in there that can go bad. Once I put the jumper on the column my horn blows loud everytime. For what it's worth.
John
Lead Driver
Joined: Aug 2003
Posts: 6,305
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From: Boulder Creek, Ca
If all else fails, suggest clean surfaces that come in contact with the horn brush, both horn button, and spray small amount of electrical cleaner down the brush housing. Word of caution, carefull wire on brush is designed to break off, fragile. There is also 3 set screws for adjusting the button. Anyhow, horn on my 65 would work intermittently, if at all, for years until about 6 months ago when I went thru the steps mentioned and has work great since.
dave
dave
Logistics Pro
Joined: Dec 2004
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From: Hemet ca.
When installin a big rig air horn I ran into a situation regarding a relay. I ran the wires according to diagram I mounted everything according to diagram / instructions, but no sound After pulling out remainder of my hair I tried jumping terminals at relay and the horn worked. So .... bad relay after replacing relay horn works perfect and loud.
check relay may just need to replace it.
check relay may just need to replace it.
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Thanks for all of the solid advice. With all the rain we have had today and yesterday, I haven't had a chance to get under the hood. Next weekend I will give it a shot and have bought a new relay ($10) in anticipation that that may be the problem.
Now if only I had a small robot that could crawl into the fender wall and remove the barrel/slip nuts on the fender emblems. My forearms are pretty useless so far.
Now if only I had a small robot that could crawl into the fender wall and remove the barrel/slip nuts on the fender emblems. My forearms are pretty useless so far.
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Logistics Pro
Joined: Dec 2004
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From: Hemet ca.
Originally Posted by jowilker
Robert, Ya gots me wondering how a relay works with an air horn? All of the ones that I have seen all use a mechanical air valve.
John
John
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C4AZ-13853-A .. Horn Relay (Motorcraft HB-79) Rectanglar 1 1/2" x 1" metal cased housing with plastic cover where spade connectors are. 1964/66 = Mounts on right fender inner apron about a foot rearward of the core support.