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Can anyone explain how a horn system works and how it is to be wired. When I first got the 71 Nova the horn did not work. I replaced the horn and the horn relay and it worked. Not exactly great but it worked. When you pushed the horn button the horn would blow but was kind of muffled. If you touch a hot wire to the horn it blows clear and loud. Well now the horn doesn't blow at all. Questions. Does the horn button act as a ground or is it hot? What does a horn relay do? how do I test the system to find out what the problem is?. By the way the horn relay is located near the power break and not by the radiator as 71's should be. Does the horn relay have to be grounded? right now it just floats in mid air with the wiring holding it in place. Real shoddy!
 

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Deluga10 said:
Can anyone explain how a horn system works and how it is to be wired. When I first got the 71 Nova the horn did not work. I replaced the horn and the horn relay and it worked. Not exactly great but it worked. When you pushed the horn button the horn would blow but was kind of muffled. If you touch a hot wire to the horn it blows clear and loud. Well now the horn doesn't blow at all. Questions. Does the horn button act as a ground or is it hot? What does a horn relay do? how do I test the system to find out what the problem is?. By the way the horn relay is located near the power break and not by the radiator as 71's should be. Does the horn relay have to be grounded? right now it just floats in mid air with the wiring holding it in place. Real shoddy!
What kind of steering wheel do you have? I BELIEVE the horn wire is a ground. On an aftermarket wheel, like I have, there is a little spring in there and if that doesn't hit the metal tab on the horn wire, its a no go. My horn wouldn't work at all for a long time. I then switched wheels, found the instructions for it on the 'net, wired it up, and its like a new horn!

If your wheel is stock, maybe you could find a diagram of the parts in it? I know for a FACT you can do this with an aftermarket wheel. My horn went from NOT working at all to sounding like a brand new horn because I had something to refer to.
 

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Do the same test as you did before "If you touch a hot wire to the horn it blows clear and loud". If this makes the horn work then the problem is from the connection on the horn to the relay, inside the relay, or where the relay is getting power from.
If the horn doesn't work with a jumper wire off of the battery then the horn might not be grounded well or the horn is broken. Loosen the horns mounting bolt slightly, twist the horn bracket to get the head of the bolt to dig into fresh metal and then tighten it back down. Now try the jumper again. If it's still not working remove the horn and ground it right to the battery negative terminal and run a jumper from the positive post to the horns wire connection/terminal. If it's still not sounded, get a new horn.

The horn relay I believe does not have to be grounded. It does though have a mounting bracket on it to secure it and also to allow it to be positioned so water cannot easily get inside. If it's mounted upside down then water can get inside of it and cause damage. The reason I say I believe it doesn't have to be grounded is some horn relays are also acting as a key buzzer on some years. I just don't have any wiring books handy.
One terminal on the relay will be a constant 12V (battery voltage), another terminal will go to the horn(s), another terminal goes to the horn button in the steering wheel. Another wire may be present and be tied into the ignition switch for the key buzzer.

You can relate the wiring of the factory horn relay to an aftermarket relay with terminal 30 going to the battery, terminal 30 jumpered over to terminal 85, terminal 87 would then go to the horn(s), and 86 if grounded connects terminal 30 to 87 and the horn sounds.

Jim
 

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My horn wasn't working when I got the nova, I wired it back as it should have been and worked a few times then dead. I then replaced the relay with a new one. It worked when I tested it and weeks later (second time I used it) when I tried to use it it was out again. Those relays aren't cheap so I'll have to try a regular relay as suggested.
 
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