Help with horn please
Thread Starter
Racer
Joined: Jul 2013
Posts: 423
Likes: 6
Help with horn please
The horn on my 78 didn't work when I bought it, I started trying to figure out why.. they do sound if i jumper 2 wires togeter in the relay connector, so I bought a new relay and they still don't work bt pushing on the horn button.. I took the button off and took some pictures .. from diagrams I have seen it looks like everything is there.. Can anyone see something that doesn't look right ? I can take more pictures if needed .. Thanks
Race Director
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In the first picture the round white piece to the left side should be the horn contact and should be metal, in you picture it is hard to tell. If you touch that piece to a ground the horn should sound. See the link below of the part I am referring to.
http://www.ecklerscorvette.com/corve...1969-1982.html
http://www.ecklerscorvette.com/corve...1969-1982.html
Thread Starter
Racer
Joined: Jul 2013
Posts: 423
Likes: 6
In the first picture the round white piece to the left side should be the horn contact and should be metal, in you picture it is hard to tell. If you touch that piece to a ground the horn should sound. See the link below of the part I am referring to.
http://www.ecklerscorvette.com/corve...1969-1982.html
http://www.ecklerscorvette.com/corve...1969-1982.html
Racer
Joined: Jan 2013
Posts: 300
Likes: 10
1. When you press the horn button can you hear the relay click?
2. If yes go to the horn (either one) and put a voltmete on the horn and press the button if you get a voltage reading of 9-12v it probably is the ground wire on the horn, disconnect the wire from ground and clean the terminal and the area it goes against when screwed down.
3. If the relay isnt clicking put a voltmeter on the wire from the horn button to the relay press the horn, if you get voltage reading it probably is the relay, if not its from the fuse to the horn button or between button and relay. The wire from the fuse to the horn button should always have voltage
4. remove the horn and connect a battery charger to it - if it blows its OK if not buy a horn.
2. If yes go to the horn (either one) and put a voltmete on the horn and press the button if you get a voltage reading of 9-12v it probably is the ground wire on the horn, disconnect the wire from ground and clean the terminal and the area it goes against when screwed down.
3. If the relay isnt clicking put a voltmeter on the wire from the horn button to the relay press the horn, if you get voltage reading it probably is the relay, if not its from the fuse to the horn button or between button and relay. The wire from the fuse to the horn button should always have voltage
4. remove the horn and connect a battery charger to it - if it blows its OK if not buy a horn.
Le Mans Master
Joined: Aug 2006
Posts: 7,426
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Disconnect the harmonica connection.
Check for continuity from the round horn contact in the steering wheel to the black wire at the harmonica connection on the half that goes up the column.(connection G).
If good then ground the other side of the harmonica connection. The horn should sound.
If not then check for a break in the black wire between the harmonica connection and the relay.
At the relay:
Black is ground.
Red is hot (12 volts positive).
Green goes to the horns.
http://www.vetteprojects.com/bmv/mis...tte%201978.pdf
Last edited by Peterbuilt; Oct 18, 2013 at 09:53 PM.
Burning Brakes
Joined: Apr 2013
Posts: 926
Likes: 2
From: Castle Rock CO
Just a few months ago I had to replace the horn switch on my 1977. The switch is the same for many model years. Looking at your pictures it does not seem assembled properly probably by the previous owner since has never worked. The assembly is still fairly fresh in my mind since I did it back in August of this summer.
The metal is bent and it should be flat. It also appears the shims are in the wrong place which is why the metal became bent. I would purchase a whole new horn assembly and start with fresh parts. These are the parts I would purchase to fix it.
The screw closest to your thumb is metal is bent down
http://www.ecklerscorvette.com/corve...Product_Viewed
http://www.ecklerscorvette.com/corve...1967-1982.html
The metal is bent and it should be flat. It also appears the shims are in the wrong place which is why the metal became bent. I would purchase a whole new horn assembly and start with fresh parts. These are the parts I would purchase to fix it.
The screw closest to your thumb is metal is bent down
http://www.ecklerscorvette.com/corve...Product_Viewed
http://www.ecklerscorvette.com/corve...1967-1982.html
Thread Starter
Racer
Joined: Jul 2013
Posts: 423
Likes: 6
Just a few months ago I had to replace the horn switch on my 1977. The switch is the same for many model years. Looking at your pictures it does not seem assembled properly probably by the previous owner since has never worked. The assembly is still fairly fresh in my mind since I did it back in August of this summer.
The metal is bent and it should be flat. It also appears the shims are in the wrong place which is why the metal became bent. I would purchase a whole new horn assembly and start with fresh parts. These are the parts I would purchase to fix it.
The screw closest to your thumb is metal is bent down
http://www.ecklerscorvette.com/corve...Product_Viewed
http://www.ecklerscorvette.com/corve...1967-1982.html
The metal is bent and it should be flat. It also appears the shims are in the wrong place which is why the metal became bent. I would purchase a whole new horn assembly and start with fresh parts. These are the parts I would purchase to fix it.
The screw closest to your thumb is metal is bent down
http://www.ecklerscorvette.com/corve...Product_Viewed
http://www.ecklerscorvette.com/corve...1967-1982.html
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Racer
Joined: Jan 2013
Posts: 251
Likes: 33
78vette,
In your second post you said you made contact between the spring loaded horn contact post and ground. If everything was correct in the circuit the horn should have sounded yet you had no horn. The horn circuit through the steering column is a ground circuit. The ground needs to be made down the steering column and down through to the frame. The ground path must make it through or across the RAG joint that connects the steering column to the steering gear box. As a quick check use a meter to see if you read continuity from the steering column to the steering gear box, if yes then the rag joint is not your issue and the issue is likely in the column. If no then try using a jumper across the rag joint and then recheck if your horn works. If the answer is yes then run a wire from one side of the rag joint to the other and then the horn should work. Lots of luck, Russ.
In your second post you said you made contact between the spring loaded horn contact post and ground. If everything was correct in the circuit the horn should have sounded yet you had no horn. The horn circuit through the steering column is a ground circuit. The ground needs to be made down the steering column and down through to the frame. The ground path must make it through or across the RAG joint that connects the steering column to the steering gear box. As a quick check use a meter to see if you read continuity from the steering column to the steering gear box, if yes then the rag joint is not your issue and the issue is likely in the column. If no then try using a jumper across the rag joint and then recheck if your horn works. If the answer is yes then run a wire from one side of the rag joint to the other and then the horn should work. Lots of luck, Russ.
Burning Brakes
Joined: Apr 2013
Posts: 926
Likes: 2
From: Castle Rock CO
I am thinking the shims should be up were the bent metal is if I remember right. The shims are there so you do not bend the metal when installing the horn assembly.
Looking at the pictures they are installed so that the horn button cannot wobble and that is what is needed to make the horn work. The Horn assembly needs to wobble so that plunger and spring assembly can work.
I used the 3 factory shims when I replaced my horn assembly and I also had to use the factory plunger because the one that came in the kit was just like an 1/8 of an inch too short. I had to play with mine a few times to get it working again.
I had the opposite problem the Horn Assembly Plastic had dry rotted and my horn was blowing all the time when it broke.
Entertaining to say the least. I was sitting at a red light when it broke and I was 4 cars back. My horn started to just sound off and then all the way thru the next 2 intersections I had to drive and steer while holding on to my horn. Blowing on and off until I was able to pull into a parking lot and disconnect the horns. To others I must have seemed like an inpatient driver
Looking at the pictures they are installed so that the horn button cannot wobble and that is what is needed to make the horn work. The Horn assembly needs to wobble so that plunger and spring assembly can work.
I used the 3 factory shims when I replaced my horn assembly and I also had to use the factory plunger because the one that came in the kit was just like an 1/8 of an inch too short. I had to play with mine a few times to get it working again.
I had the opposite problem the Horn Assembly Plastic had dry rotted and my horn was blowing all the time when it broke.
Entertaining to say the least. I was sitting at a red light when it broke and I was 4 cars back. My horn started to just sound off and then all the way thru the next 2 intersections I had to drive and steer while holding on to my horn. Blowing on and off until I was able to pull into a parking lot and disconnect the horns. To others I must have seemed like an inpatient driver
Last edited by MakoJoe; Oct 19, 2013 at 08:42 PM.
Race Director
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From: South Western Ontario
The horn button assembly may be buggered, but you first have to get it working so that grounding the contact pin as shown in your first picture makes the horns work. That contact is the other end of the black wire at the horn relay. Test between both ends with a continuity meter.
To check the horn relay, you can disconnect the harness and then ground the terminal where the black wire connects. The relay should click. The horns should sound if you ground that terminal with the harness connected.
To check the horn relay, you can disconnect the harness and then ground the terminal where the black wire connects. The relay should click. The horns should sound if you ground that terminal with the harness connected.
Race Director
Joined: Apr 2007
Posts: 11,152
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From: South Western Ontario
Unplug the relay and jumper the red to green to make the horn blow. Next is connect the relay and test it by connecting the black wire to ground at the relay. The last is to test the black wire to the column by grounding that button in the column.
For some reason I though your car was the older relay with screw terminals for the power and a 2 wire plug for the horn and horn button wires. Forget what I posted about grounding the terminal with the plug off on your relay.
For some reason I though your car was the older relay with screw terminals for the power and a 2 wire plug for the horn and horn button wires. Forget what I posted about grounding the terminal with the plug off on your relay.
Thread Starter
Racer
Joined: Jul 2013
Posts: 423
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Unplug the relay and jumper the red to green to make the horn blow. Next is connect the relay and test it by connecting the black wire to ground at the relay. The last is to test the black wire to the column by grounding that button in the column.
For some reason I though your car was the older relay with screw terminals for the power and a 2 wire plug for the horn and horn button wires. Forget what I posted about grounding the terminal with the plug off on your relay.
For some reason I though your car was the older relay with screw terminals for the power and a 2 wire plug for the horn and horn button wires. Forget what I posted about grounding the terminal with the plug off on your relay.
Le Mans Master
Joined: Aug 2010
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From: Central Texas
Thread Starter
Racer
Joined: Jul 2013
Posts: 423
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[QUOTE=Street Rat;1585233175]I got so frustrated trying to diagnose mine that I did just that. I mounted it on the turn signal lever. 
[/QUO
I'm going to get one.. What did you connect to ? I'm thinking about connecting to the red and green wire in the relay connector..
[/QUOI'm going to get one.. What did you connect to ? I'm thinking about connecting to the red and green wire in the relay connector..
Thread Starter
Racer
Joined: Jul 2013
Posts: 423
Likes: 6