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Phantom horn blowing

dog walker

New Member
Joined
Oct 7, 2014
Messages
3
I recently repaired a broken connection to my horn. After putting the horn relay back in, horn worked properly.

The other day, my son borrowed the vehicle and at 5:00am, the horn came on and wouldn't stop. No one had gone near the Cruiser. He finally disconnected the battery. Later, he removed the horn.

Can a short in the horn cause this or could a bad relay trigger this? I hope it isn't in the steering wheel hub.

Anybody help?
 

tjtfaulkner

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Joined
Mar 29, 2014
Messages
16
most horns have a constant live feed and are switched by connecting to earth, so if you have a wire rubbed on a sharp edge it can operate the horn.
 

dog walker

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Oct 7, 2014
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3
Thanks for the response. I assume the single wire to the horn is the live feed. Do you refer to a ground "short" in this wire or somewhere else?
 

tjtfaulkner

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Mar 29, 2014
Messages
16
if it is a single wire on the horn then my previous post doesn't mean anything. the single wire must supply voltage for the horn to work, it will earth at the bolt holding it on. if wires have rubbed or got damaged it could get power from a wire beside the horn wire. can be very hard to find. if you think it is a relay there may similar relays for other things, you can swap the relays over to see if the relay is stuck on.
 

dog walker

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Oct 7, 2014
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ok. I will swap out relay next. What is the purpose of the relay vs. a regular fuse?

Thanks.
 

BobMurphy

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Mar 1, 2010
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What is the purpose of the relay vs. a regular fuse?

You still need a fuse.

Some of the electrical gear in a car require a high current. If they were simply connected via a switch (with an in-line fuse) the switch would have to be substantial enough to carry the high current. It is current (Amps) that generate heat.

A relay separates the electrical load from the switch. The relay has substantial contacts and is connected between the load and the power source. The switch simply activates the little solenoid that closes the contacts.

Thus, the switch is protected and the risk is carried by the relay that is a relatively simple thing that is easily replaced in isolation.

Still annoying when they fail though :icon-rolleyes:.

Bob.
 
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drbob101

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Joined
May 13, 2014
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8
I was awaken by the police one morning recently and the horn was just going off. I dc the battery and ultimately pulled the relay. no horn .

I went through an EFI fuse issue and cleaning and changing that fuse fixed that porblem (other thread), the horn relay is right next to the EFI relay so now I am thinking the horn issue may be related to the same fuse box issue as the efi was.
 
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