Another Horn Question..Help

[CNP934DC]

Still trying to get my horns working. (48 Plymouth). Previous owner must have been tinkering and had a 3 prong relay set up. I purchased a NOS 4 prong as shown in the P-15 wiring diagram. So, I have 3 wires to work with. Thinking about disconnecting all the existing and running new wires for everything. I have the horns (H) marked on the relay, coil, ( marked, and ammeter, (S) marked. Where can I find the connection to the horn button. Everything's wired through harnesses and I don't want to disturb them. Had my neighbor pressing the horn ring with the key on last night but no combination seemed to work. What is the fourth prong (not marked) supposed to be? Ammeter or horn button. I'm confused. Any suggestions? I am ready to wire direct to battery and mount a button under the dash out of frustration.

[Norm's Coupe]

Did you run a test to see if the horns actually worked without the relay. They should blow without the relay if you hook them directly to the battery. If not they either need cleaning or adjusting. So.........before you start rewiring, I'd run that test first. The relay and wiring may be good.

[CNP934DC]

Yep, ran a wire from battery to horns and they woke up the whole neighborhood.

[Norm's Coupe]

I would test the horn button the following way.

Remove the horn button and ring. It's only held on by 3 screws on the back of the steering wheel. Then I would run a jumper wire outside the car from the relay to the steering wheel horn works. Touch the wire to make the connection and see if the horn blows. If it does, it's probably a problem with a broken wire going through the steering wheel shaft and out the bottom of the steering box. If that's the problem, just pull that wire and run a new one to the relay.

[CNP934DC]

Thanks. I'll give that a try. And that fourth terminal?? H, B, S, and what? I think this was discuused on another thread sometime back but can I get definition of the four to make sure I'm reading the diagram right?

[aero3113]

I recently installed a set of horns in my 50 plymouth and thought they did not work.I was only pushing on one side of the horn ring, When I pushed down on both sides of the horn ring at the same time the horn worked!

[BobT-47P15]

As Norm said, the wire to the horn button runs thru the steering column and

out thru the steering box. Here's a wiring diagram that should show the

four connections for horn relay. I followed it when hooking mine up.

[Merle Coggins]

On the 3 wire setup you had one power feed (probably battery hot from the regulator or ammeter), one ground (to the horn button), and the output to the horns. The power wire feeds both the switching contacts and the pull coil. The horn button would provide the ground for the pull coil in the relay so that it'll pull the contacts closed and connect the power supply to the horns.

On a 4 terminal relay you have separate power feeds. One main power (same power feed from your original relay) for the switch contacts and one power feed for the pull coil. In Bob's schematic it looks like the coil power comes from the ignition at the coil. The other two would be the same. Ground for the pull coil goes to the horn button and the last one, from the switch contacts, goes to the horns.

I can't tell you which one is which on your relay, but you can figure it out if you have an ohm meter. Check between two terminals at a time with the ohm meter. When you find the two contacts for the pull coil you will see resistance, probably somewhere in the 20 - 60 ohm range. The other two will then be the switch contacts. If you connect your ohm meter to the other two it should read as an open connection. Then supply a voltage and ground to the two terminals that showed resistance between them. This should activate the coil and close the contacts. Now your ohm meter should read close to 0 ohms with the contacts closed.

Now that you know which terminal is which you can wire it up. Using Bob's schematic, connect a wire from the ignition power (from the - side of the coil) to one of the relay coil terminals. The other relay coil terminal goes to the horn button. The other two terminals connect to your main power source and the horns.

I hope this helps more than it confuses.

Merle

[steveplym]

Here's a pic of my relay. I'm not sure about the H, S, B terminals. I do know that the top left terminal connects to both horns.

One wire has to go to the ignition switch, another to the ammeter, then the other to the wire that comes out of the bottom of the steering column.

I replaced that wire when re-wiring my car. Bottom of it was damaged and needed replaced. Like Norm said if you remove the three bolts from the back of the steering wheel you can access the wire.

[Young Ed]

Keep in mind there are 2 locals for horn relays on the p15s. The later cars have it next to the starter relay under the hood. If you look at a wiring replacement site like RIwiring they show 2 different harness's for P15s. Some of the connections may vary. I can't recall if any were horn related but when I redid my wiring this spring there were a few things that didn't match up to the diagram in the shop manual.

[CNP934DC]

Thanks All. Lots of stuff to check out. If you hear a loud blast coming from Western PA in the next few days, don't be alarmed. It'll be the P-15's honkers, (or me screaming). Wish you guys lived next door. I'd keep you busy. LOL

[james curl]

When wired properly the ign. must be on to energize the horn relay. If the key is in the off position the horn will not blow with the four wire relay.

[Norm's Coupe]

I recently installed a set of horns in my 50 plymouth and thought they did not work.I was only pushing on one side of the horn ring, When I pushed down on both sides of the horn ring at the same time the horn worked!

Actually, you should be able to push the ring in any one single spot to blow the horn. If not, something is wrong inside the horn button so it's not making contact. You should not have to press two sides of the ring to make the horn blow.

[BobT-47P15]

You probably have two or three screws on the back side of the steering

wheel hub holding on the horn center and ring. You might first try either

tightening those just a little, or loosening them just a little - see if it

makes any difference about how/where you press.

Otherwise, you may not have some part inside the horn center installed

just right. Those items in there can be just a little tricky sometimes.

[greg g]

There is a old style push in connector on the wire coming out of the steering colume/box. The wire coming out is only a couple inches long and goes to a plastic connector. If this connection is broken, no ground no beep beep. hard to find under the battery tray take a good close look and make sure its connected there.

[CNP934DC]

Shel Bizzy, thanks. I think the diagram you posted answers the problem. I have S and IGN switched and my horn button wire is MIA. Be on a search mission this week-end but that may also explain why the 3 prong wasn't working either. Geez, I may have two working relays.......huh!