'47 Plymouth horn relay.....

[BobT-47P15]

Anyone happen to have a four contact horn relay lying around that you

don't need??? Am fixing up a second set of horns and upon taking them

from the storage building where they've resided for a few years, I found

that the relay was broken on the top, two contacts are missing.

They look like this.

Mounts between the horns on the brace.

If anyone has such a thing, you can PM me if you wish.

Thanks.

Bob

[Plymouthy Adams]

Bob..let me look out in my stuff...I forgot last week when you mentioned you were in need..my bad...get back with you in a minute..will look upstairs now

[RobertKB]

Bob, if Tim does not have one, I have three spares that I know work as I tried them all on my own car. PM if interested.

[Plymouthy Adams]

guess what I found upstairs in the bit bucket?

[BobT-47P15]

I give up --- what???

A horn relay??? Big ol spider????

[Don Coatney]

I sold the one from my car on a forum auction earlier this year.

[james curl]

I bought two 12 volt four terminal relays from Radio Shack, I have one for my horns on my 48 P-15 and another for the overdrive on my 55 chevy pick up. They are use a circuit board solid state and are very reasonable in price.

[BobT-47P15]

But what will be the result if you use a 12V relay in a 6V system??

Will horns be louder or softer in volume???

They only get short bursts of power anyway.

Unfortunately, I don't know if you can substitute one sort of relay for another....as they seem to be

designated for certain specific things by the manufacturer.

[Plymouthy Adams]

If a 12 is used in a 6 application..if the coil energizes..you transfer 6 volts....

[BobT-47P15]

I looked in a box of relays purchased at a swap meet a couple years ago and it looks like a new aftermarket 12 volt horn relay in there. May try it to see

what it does, but still prefer to get a correct 6 volt one. Think I'll take

pictures of the other relays and post them - maybe someone could use

one of them. A couple have fuses and appear to be for older models.

[Norm's Coupe]

Bob,

Until now I always thought as you do. You need a 6 volt relay for 6 volts, and a 12 volt relay for 12 volts. However, after reading Tim's post and thinking about switches I don't think it matters. After all a switch works on 6 or 12 volts, it doesn't care. A relay is basically doing the same thing, transferring electrical current when it's turned on. So, I'm going to agree with Tim on this one. A relay probably doesn't care either how much voltage is put through it as long as it's big enough to carry that voltage. The ones with the fuses wouldn't matter either. Usually a fuse is there to control the amount of amps you run through the relay, not the voltage.

[BobT-47P15]

The only thing about the older ones is the connectors.....they have

different letters than a horn relay. I wonder if they're for headlights,

since they have fuses. And the brackets on them are made a little

differently..... Not a real big deal, just one more little thing that can

be a learning experience--- for me anyway.

[Norm's Coupe]

You are probably right about the ones with the fuses being headlight relays. Post a picture of one or more of them. I have a couple spare headlight relays and both are different from the one I have on my coupe.

[BobT-47P15]

Where is a headlight relay on a P15????

[Plymouthy Adams]

good question..

[Norm's Coupe]

Actually, you could put the relays almost anywhere under the hood or under the dash. Mine was under the hood when I bought the car, so it's still there. Below is a picture of where mine is mounted. It's the little long box with the fuse on top. This a Delco brand relay, but there are others and they are also shaped differently. This picture was taken before I cleaned everything up and painted the engine compartment. Don't have one of that area afterward.

[Plymouthy Adams]

Figured you may have had one...just wanted folks not looking for something not stock...

[BobT-47P15]

Norm, I wonder if yours was added later since the fuse on a P15 is on

the end of the headlight switch.....

[Norm's Coupe]

Bob,

I really can't answer that question as to when the relay was added. Since I've never had a problem with the lights, I've also never checked the wiring diagram to see if they show it. All I know for sure is, my switch knob is original. I've never really looked at the switch to see if there is also a fuse on it either. However, don't remember seeing a fuse on it when I was doing other things under there. I could be wrong though about that. Also, as you can see by the looks of things in that area, it was there a long time. I do believe though that it was added after the car was built, like most relays in that time period.

From what I understand about the relay's a lot of people added them to their 30's and 40's cars back then, because they were supposed to make the lights brighter. Does it make my headlights brighter? Who knows, I've never tried the lights without it, so have nothing to compare them to.

[martybose]

I added a headlight relay when I upgraded to 60W halogen headlights, because both the headlight switch and the dimmer switch were getting hot. Apparently the original headlights were only 30W, and that's what the switches were designed for. I also upped the size of the wiring from the relay to the headlights.

Marty

[BobT-47P15]

OK, now I wonder if adding one of those relays in the headlight wiring

system would make the lights brighter. Would just have to figure out

how to attach the wires and which wires to use. Not sure how many

wires go forward from the switch to the connection terminal just behind

the grille. The wiring diagram should contain the answer.

[BobT-47P15]

P15 electrical system overview......

P15 wiring diagram......

[Norm's Coupe]

Bob,

It's been awhile since I looked at the wiring setup for the headlight relay on my coupe. However, it appears the wires coming from the headlights are hooked up to the terminal next to the relay. Also the wires coming from inside the car appear to be hooked to the terminal. Then there are two other wires hooked from the terminal to the relay. If you enlarge that picture I posted you might be able to see how they are hooked up.

[Jim Yergin]

Bob,

I installed Auto-Lite headlight relays in my '41 P12. The headlight wire from the high/low beam switch runs to the relay to operate the relay switch. Then there is the headlight power source wire and the wire to the headlights that the relay switch connects when it is engaged. The relays I used are single purpose so I had to install two of them, one for the low beams and one for the high beams.

Jim Yergin

[martybose]

I found a setup meant for headlights that has 2 relays in one enclosure. I've used it in both 6V and 12V.

Marty