Horns weren't working...now they work continuously!

[Redmond49]

I've been trying to get the horns to work on my P15 - they did not work at all. So I ran all the procedures in the service manual for diagnosing a horn that won't sound. At each diagnosis step, the horn sounded or the lights on the tester lit up; in this case, the manual says to replace the horn relay.  So, I've replaced the horn relay with a NOS one just like the one that was in the car. Now, when I turn the ignition on, the horn sounds continuously and stops when I press the horn ring down on the steering wheel. So, I guess it did need a new horn relay!

 

The wiring diagram shows 4 lines into or out of the horn relay:

 

- Wire to the horns

- Wire to the negative ignition coil terminal

- Wire to the horn button

- Wire to....I'm not sure how to read this last one. In the diagram, the last wire goes across the big black cable that goes from the battery to the solenoid switch; the wire line passes very close to the solenoid switch and then goes on to the ammeter. 

 

On my car, this last wire is connected from the B terminal on the horn relay directly to a post on the solenoid switch, and the big battery cable is connected to the same post. 

 

And, I have a fifth wire connected to the same post as the negative ignition coil wire. This fifth wire joins a bundle of thick green and red wires that run back through the firewall. I tried disconnecting this fifth wire just to see what happens, but then the horn doesn't work at all. And, the hood ornament light no longer comes on when I turn on the ignition.

 

Thoughts? Is the extra wire the positive ground perhaps? I'm wondering if the extra wire is some hack to get around the old broken relay so that the car would start. But it doesn't look like a hack wire since it seems to be the end of a legit wire that runs back with other legit wires back through the firewall.

Edited November 15, 2013 by Tyson

[_shel_ny]

If you look real close at the mounting tabs for the relay they are marked as to where they go.

 

Bat, horn, ign, gnd

 

Extra wires may be just a "common point" electrical connection.

 

 

 

 

Edit: Seems like you have everything where it belongs.

 

         Horn stops when you press the horn button sounds like a little misalignment of bits and pieces under the horn button.

Edited November 15, 2013 by shel_ny

[greg g]

The horn button is supposed to be the ground that energizes the relay.  You might have one of the wires connected to the wrong terminal,  Thee is a wire that come out the bottom of the steering box.  This is the connection for the horn button.  There should be a old style butt connection in the wire near the box.  If you unhook that there should be no power on the steering column side but the sire on the horn side of the connection should have power with ignition on.  When you ground this it should sound the horn. when not grounded that should only be power at the batt  terminal.  As the relay should not be grounded with an open circuit in the horn button wire the internal electromagnet switch should not be energized.  If there is power to the horn out terminals you have a problem.

[Redmond49]

The wire from the steering is plugged into the round connector at the bottom of the horn relay; the wire to the ignition coil is on the other connector at the bottom that has a nut that screws down on a threaded post. I have the wire to the solenoid and battery connected to the B terminal, and the wire to the horns is connected to the H terminal.

[Frank Elder]

........

[_shel_ny]

That's the way it should be connected.

 

Still seems to me that the problem is under the horn button. You are providing a ground, and when you move the horn button the ground is being interrupted.  Something out of position under there.

[Redmond49]

I pulled the horn button wire, disassembled the horn ring bits, taped a few cracked wires and put it back together and it works fine now. I guess it just needed a little love.

[RobertKB]

Glad you got it working. A little TLC often works wonders with our old cars.

[Tom Skinner]

One fine Saturday morning when I was pulling out of my garage with my '48 the horn just kept blasting.

Of course I jumped out and unplugged it at the bottom of the post at the connector down there to quiet the street.

It turns out the insulation at the bottom of my horn cup had worn off from the spring rubbing it down to the metal.

So that's one more place to look if your horn just go's off and won't stop. It seems the very bottom of where the spring pushes back off

of an insulated horn cup - that insulation may dry out crack or fall away and cause such a situation. I knew I had replaced the wire down through the 

post just before that so I was looking elsewhere for the problem. I taped the cup and spring with electrical tape to fix it, but at some time in the future

it may wear back through the tape and a piece of rubber would probably serve better as a repair - say about the size of a silver dollar is round.

[Redmond49]

Interesting. There's no insulation between the spring and the horn cup on my car. The spring is directly in contact with both the cup and the contact plate. When you press the horn ring, the spring is pushed away from the contact plate and that seems to be what activates the horn, I think.

[Tom Skinner]

Tyson,

When you press the Horn Bar the Ground is completed and the Horn Sounds.

That Spring merely keeps your Horn Bar off the Grounding Process

That Insulation is very hard to determine, Look closely it is there, perhaps colorless

but none the less its there. I believe theres even a blow up picture in your Service Manual of it

Tom

[doctor dirt]

Thanks for the info, spent some time on my signals and wipers the other day and I think I found the weal spot in the wiring. Everything is working again and thats rare, however on the way home from my friends garage the horn began to "sing"! Without me touching the ring hahahaha!!! Not on a turn just intermitently driving straight down the road. Now the horns are one of the few things that worked beautifully on this car since it arrived!! My best guess is that its "their turn" to bother me! HA! Doc.

[Redmond49]

Thanks for the info, Tom. 

[jcmiller]

I've got a similar problem and it has me stumped.  When I connect the wire leading out of the column to the relay, the horn sounds continuously.  I thought that meant there is a short circuit somewhere in the column or at the button.  My thinking was that, in normal operation, pushing the button is supposed to establish the ground to make the horns go, but instead I must have a loose wire or something similar causing it to be grounded already.

 

But when I took apart my horn button, it seems that it is designed to disconnect a circuit rather than establish one.  IE, the spring is held tight between the ground cup and the contact plate.  When I press the button it looks like the spring is pushed away from the contact plate, breaking the connection.  I thought it was supposed to be the other way around, no circuit until button pushed.  I've got an exploded-view diagram and it seems to be put together correctly.  I guess my question is: is the button supposed to establish a circuit or break one?  (I don't really understand how breaking a circuit would cause the horn to blow, but perhaps there is some trick.)

[DonaldSmith]

The horn button or ring makes the connection to ground.  I know, it had me baffled.  

The secret is that when the button or ring is in the normal position, the metal with which it is in contact is insulated from ground by the steering wheel, which is plastic.  When the button or ring is disturbed, it makes contact with grounded metal.  Or else it's just magic. 

[jcmiller]

I don't see any insulation on my ground cup either, so I put electrical tape on it to separate it from the spring - now there is no horn at all.  I took the opportunity to polish up the horn ring so at least that looks nice now.  I'm going to take out that tape, put it all back together, and hope for the magic.

[DonaldSmith]

I reviewed how my horn ring works.  

The grounding wire is soldered to a round disk with two straps that secure it to the plastic steering wheel spokes,  

Without the horn ring assembly, the big spring would contact the disk, grounding the circuit.  

The horn ring has lugs which normally keep the big spring away from the disk,

When you push the horn ring, it rocks, allowing part of the spring or the horn ring to contact the disc.  

I don't know if a horn button works the same. 

[jcmiller]

Thanks Donald.  I figured the same thing out on a long, hard run this afternoon.  Sometimes you just have to step away.  It's deceptive when you take it apart because you just see the spring pushing into the contact plate, leading you to believe there is already a circuit.  But as you point out, when you fasten the horn ring back on with the hub cover, it pushes the spring down a little more - just off the contact plate. 

 

I was also using incorrect terminology.  I kept saying button to refer to the hub cover, which is not a button at all - just something that holds the horn ring down.  When I first took it apart, the 3 screws holding that down were not very tight.  Now that I have removed the tape I put on earlier, lined the horn ring lugs up carefully with the top of the spring, and fastened everything securely - it's working!

 

Thanks for your help.

[greg g]

horns blowing continuously (assuming the wiring is stock and intact) usually indicates an improper ground in the wire going up the steering column. Usually due to cracked or missing insulation connecting with the column assembly below the hron button At the bottom side of the steering box, the wire exits the column and there should be a butt connector to the wire that goes from there to the relay.  unplug that connector and make a jumper wire to test the circuit.  Connect a jumper wire tot he relay side of the connection, turn on the ignition and ground the other end of the wire,  The horn should sound when grounded and shut off when the ground is disconnected.  If that works, the fault is in the wire going up the column to the horn button.  This wire can be replaced by tying a new wire to the end that goes into the steering box and then pulling out the old wire (which will feed the new one through) out of the column from the top with the horn button off  I suppose you could also do it by connecting the new wire to the old one and pulling it through from the steering box end also.  But DO NOT just pull the old wire out under any circumstances.   

[Bob Riding]

I had the same problem with the horn honking continuously during my initial wiring of the '40 Plymouth wagon and couldn't figure out why. After checking and double checking everything, I found the problem...it turned out to be the screws I replaced that held the brass T to the steering wheel were too long and were making contact with the internal metal of the wheel, hence grounding it out and honking continuously. Once I ground down the points, the horn would only honk when I pushed the horn blowing ring.

(quote name="greg g" post="356982" timestamp="1389626762"]horns blowing continuously (assuming the wiring is stock and intact) usually indicates an improper ground in the wire going up the steering column. Usually due to cracked or missing insulation connecting with the column assembly below the hron button At the bottom side of the steering box, the wire exits the column and there should be a butt connector to the wire that goes from there to the relay.  unplug that connector and make a jumper wire to test the circuit.  Connect a jumper wire tot he relay side of the connection, turn on the ignition and ground the other end of the wire,  The horn should sound when grounded and shut off when the ground is disconnected.  If that works, the fault is in the wire going up the column to the horn button.  This wire can be replaced by tying a new wire to the end that goes into the steering box and then pulling out the old wire (which will feed the new one through) out of the column from the top with the horn button off  I suppose you could also do it by connecting the new wire to the old one and pulling it through from the steering box end also.  But DO NOT just pull the old wire out under any circumstances.

[doctor dirt]

Got it done, didn't realize I had to get down to the steering box too! Alot of work for a horn hahaha!!!! The design is actually a good one and after tuning my horns they sound terrific.

 

 

Hello everyone I'm back on my feet (both of them) and feeling fine. I had a bad month or so but doing ok. The car has progressed with my friends giving it some time, the horns, lights, wipers and clutch adjustment have been attended to.

Searching for the Radio Repair shop I found months ago but seem to have misplaced that info.

Oh well I find it, going to try to take some pics of the car top and bottom. See ya soon, Doc.

[DLK]

Got it done, didn't realize I had to get down to the steering box too! Alot of work for a horn hahaha!!!! The design is actually a good one and after tuning my horns they sound terrific.

 

My horns didn't work at all so I took the lazy way out and bypassed the steering column and put a button under the dash to sound the horns.  Works great except when I need to quickly lay on the horn. At least I kept all the parts in the steering wheel intact so if I ever get sufficiently motivated I can fix the problem rather than Band-Aid it.

[Young Ed]

My horns didn't work at all so I took the lazy way out and bypassed the steering column and put a button under the dash to sound the horns.  Works great except when I need to quickly lay on the horn. At least I kept all the parts in the steering wheel intact so if I ever get sufficiently motivated I can fix the problem rather than Band-Aid it.

 

You're going to have to spend a saturday over here. We can try and fix your horn and lights.

[DLK]

You're going to have to spend a saturday over here. We can try and fix your horn and lights.

Well we plan to move before summer so once we get settled in a new place I'd be happy to swing by your way and at least have you look over the situation.  The harder issue to fix will be the turn signals.  Since the rears were not working I just disconnected all the wires.So part of the rear of the car rewire will be reconnecting the signals and getting them working.  I may be looking at 2015 for some of this but that's ok.  If i can drive it this summer with the rebuilt engine and have working stoplights I can use the arm signals for one more season.  

[doctor dirt]

Damn Horns!!! The horns have decided not to work again, I took the tiny contact screws out (points) and they seem to be worn out.

Does anyone on the forum repair (rebuild) the trumpet horns and have access to the points? The threaded end seems to have a different metal exposed and my guess is just matching the size won't get them working.

My coupe has dual trumpets and I think that someone during the restoration added them, I don't think duals came stock on a D29 business coupe'. I just replaced the relay with a more modern piece and ran all new wiring through the column and cleaned the terminal next to the radiator. Everything was working nicely for about a week then I set the car up for about 3 weeks and yesterday I had no sound. This car reminds me of me, some days everything is ok the next day its broke or simply not working well! Were the same age too.............................   "anyone got any "horn points"?????