Hot Wire

Junior

Junior

Member
Have a issue i've been pondering for a while, but haven't figured out a solution.
Pretty much finished with my 1929 Tudor frame off restoration but I have a horn problem. When connecting the yellow/black and blue/yellow wires to the horn, the horn blows continuously. The yellow/black wire is hot all the time and I assume it should not be unless the horn button is pressed. I believe the horn is working properly. After looking at the spider at the light switch body, when the horn is pressed, the blue/yellow wire is dis-engaged from the spider breaking the circuit I assume and this doesn't make sense to me. So, I am confused as why the yellow/black wire has a continuous charge. I have the wiring diagram and have been over it and over it and I am sure I have everything wired correctly. This is a 6 volt with no cowl lights harness. Any ideas to solve this issue would be greatly appreciated. I do not have much electrical knowledge, I just try to keep the smoke in the wires as best I can. Having a Model A without a horn is like having a Oreo without the creamy middle :mad:
 
The horn is hot all the time, the button completes the ground. you must have
a short to ground some place.

Bob
 
The one wire to the horn is hot all the time. The horn button, when pushed, will provide a ground connection for the horn and causes it to honk. It sounds like the problem of the horn blowing all the time is in the horn contact under the button or the connection between the end of the horn rod and the center contact in the main contact assembly at the bottom of the steering box. The wire inside the horn rod could also be shorting out.

My opinion, Chris
 
As was stated before, the yellow wire is hot 24 hours a day , 7 days a week. The blue wire connects to the springed center contact in the round black part of the wiring harness under the steering column. Here is what you can do to test your problem. Take the harness off the bottom of the column and out of the light switch. Hook up the wires to the horn. It will not be running at this point. Then attach a wire to the springed center contact of the black ring on the harness (which is attached to the blue wire coming from the horn) and connect that wire to any good ground and the horn will honk. Now you have confirmed your horn works and is wired correctly. Remove your jumper wire you just used. Now take that spring loaded part that has the blue wire on it, and touch it to the very tip of the horn rod. It should NOT honk (without pushing the horn button). If it does , then the wire INSIDE the horn rod is touching the inside of the horn rod (thus completing the ground). It is not likley that this is the case, but it is possible. If this happens, either replace the horn rod, or the wire inside it. Assuming that the horn rod is good, Now take the spring loaded end and HOLD it tight to the tip of the horn rod, and have someone else press the horn button. The horn should honk when the button is pressed. If all of this works, then your problem is that spring loaded center contact is touching the SIDE of the light switch hole (which is grounded) (a common problem on some chaep wiring harnesses). Use some shrink tube around the springy part (to prevent is form touching the metal part of the light switch) and reinstall and all should be fine.

Hope that helps. Any questions, call me.

Steve Becker
Berts Model A Center
800-321-1931
Tues- Sat
 
Do you have an ORIGINAL Model A horn, or some aftermarket horn?

Many of the aftermarket horns use the horn body as ground, and will thus blow as soon as the power wire is connected. If this is what you have, then you could isolate the horn from ground and connect the horn wire to the body.
 
Wow. Thanks for all the quick and detailed responses! The wiring harness is new as is the horn rod wiring. Practically everything on the is car is new. My dad gave me the horn as a gift so I put it on and it is a aftermarket horn. As I see them on Ebay, the original horns have two wires coming out. The aftermarket horn has one wire and the horn will not blow unless it's bolted on the headlight bar so that is the ground. So I think Tom is on the right track here. Now the question is: Can I isolate the ground by placing a rubber washer between the headlight bolt and the horn mounting bracket, connect the yellow/black (hot) wire to the horn wire and connect the blue/yellow (ground) wire to the horn body. Would that correct the problem? My first choice would be to get a restored original horn, but that might hurt dad's feelings a bit.
 
Yes, that should work, but if the rubber makes the horn vibrate too much you might find some insulating washers at the local hardware that are stiffer. You'd need a flat insulating washer on each side of the mounting bolt, and an insulating sleeve over the part of the bolt through the bracket. Two or three layers of heat shrink tubing might work for the sleeve if you don't find a correct thin sleeve.

Some guys have also removed the rear cover and found the motor wire that goes to ground and removed it from the ground, then run it outside the case and connect it to the horn button wire.
 
Turns hot that yes I will have to insulate the horn. The horn is also a positive ground so i had to switch the wires around. Thanks for all your help. Learned something new which is awesome.
 
I assumed you had a real horn. MUCH simpler to get a real horn (2 wire style). Even if you wire up that 1 wire Chinese horn and insulate it completly, it will never sound like a Model A Horn.....
 
I would prefer a original, but it was given as a gift so it will be on there for a while I guess. Sounds ok even though it blows in Chinese. Blows Ying Yohogha instead of Ahooga. Maybe I'll put a translator relay on it. :)
 
Junior said:
I would prefer a original, but it was given as a gift so it will be on there for a while I guess. Sounds ok even though it blows in Chinese. Blows Ying Yohogha instead of Ahooga. Maybe I'll put a translator relay on it. :)
Click to expand...

I like your attitude. An "original" translator relay might be a little hard to come by......maybe Hershey?:)
 
There are other threats where you might learn about original horns.
Lots of them (Due to moronic) lost the "Ah" and there is just "ooga" left....

So - Dont be sad about Ying Yohogha.
Be thankfull to your dad each time you listen to it.

Have fun Christoph

Remember Steves suggestion regarding shrink-tube
This helped me a lot back in time (once i couldnt stand
anymore that my car Ahoogaed arround every left-turn)
 
One more possibility for the horn that your dad gave you. You could always install it on your modern car and buy an original horn from Bert's for your Model A. If it's 6 volts and you install it on a 12 volt battery, you will need a resistor about 1.2 ohm and rated 35 watts or so.
 
Update and conclusion. Isolating the horn from the threaded headlight bolt proved to be a great challenge due to the very small clearance from the bracket bolt hole to the bolt. Found the best way to isolate the horn from the headlight bar is to isolate the horn bracket from the horn by placing a piece of rubber between the two. Now the horn works perfect and you can't even see the rubber piece unless you look very hard.. Thanks again for all the help and comments. Now onto brake adjustments.
 
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