medic1555

Been working on the horn issue of my '72 and I think I may have more than one problem.
Got a couple of questions and pics.

First question: Is this my horns relay? Located on the drivers side fender wall, next to the master cylinder. I unhooked the black wire connector and the green wire connector from the bottom of this relay.



Next question: My horn contact button is missing 2 of the plastic rivets. Is there any other alternatives to replace these then the OEM ones I will have to order at $8.00? Or, should I just replace the whole contact button at $22.00?



Next question: Is there only one horn on the 1972 Vettes? I can only locate one at the front, center just inside the grill.

Last question: I removed the one horn from the car. I ran a wire from a 12 v battery (+) to the spade connection on the horn and then ran another wire from the bracket hole to the (-) terminal of the battery. No sound. Bad horn?

oldsarge

1. yes
2. better to replace the whole contact, IMHO
3. Pretty sure there is only one
4. unless you did not get a good ground, the horn is probably no good. Double check by making sure you have a clean contact on both.

Mako72

My '72 came with only one horn from the factory. Pretty cheezy, lol.

medic1555

Thank you my friend! Any suggestions for a replacement horn if this one proves to be bad?

...Roger...

Except if the horn contact is an old GM one I would take it apart , clean it and replace the rivets.
I'm not liking the quality of the new contacts.
You might try banging that horn around a bit,sometimes they need a little encouragement.

medic1555

So just drill out the OEM rivets, take it apart, clean it, put new rivets back in?

...Roger...

No drilling,just push the little center out with a paper clip,you'll see how easy it is.

medic1555

Oh, I thought you were referring to the horn...got cha! Anyway, I beat the horn around like a step child and still no sound when I bench test it. I drilled out the rivets (like I thought you meant) and the inside was rusted beyond repair. What's a good source for a new horn?

Dirk68

I went though 3 'new' horn button assemblies before getting a good one. The problem is where they're made. You can get them at any of the large corvette parts houses. The C3 horn design was the real bad bad bad! I would love to whip the designers like a step child!

medic1555

Yea, seems like a pretty involved system to simply complete a circuit to the horn. Maybe they hadn't learned the KISS concept when they designed that system.

medic1555

I replaced the horn today and if I wire it directly to 12v it works. Now I think the relay may be defective. Shouldn't I have 12v at the little brass plates in the steering column? I have nothing right now so I suspect a bad relay. Ordered one today, boy are they pricey.

...Roger...

No , the horn contact in the column is a ground for the relay.
(and its not the type that seeks ground and might read 12v with a voltmeter)

Hook your relay back up and leave the black wire off,now ground the spade the black wire was hooked to-horn should blow if relay is good.

To check the black wire coming from the horn switch in the column,use your ohm meter between the black wire and ground-you should continuity when you press the horn button.
( I use a 12v test light for this test but most guys don't have them so I don't bother to post it)

medic1555

I did this test and nothing happens. So I'm guessing the relay is bad?

...Roger...

Sure sounds like it. The switch in the column just grounds that spade and providing the red wire post was hot the relay should have sent power to the green wire spade.
Sometimes you can remove the can and clean the points and save the relay.

speedreed8

i replaced the plastic rivets in my contact button after 2 broke, with plastic screws and nuts i got at home depot. put a little glue on the threads to premanently hold em.

medic1555

I pulled the green wire from the relay and touched it to the threaded stud aand the horn works that way. When I get the new one I'll try cleaning the old one and keep it as a spare if possible. Thanks for the great input!!!