Horn relay wiring

[jcmiller]

Happy thanksgiving everyone. One of the things I am thankful for is this forum and the knowledge that people are willing to share here.

The horn on my P14 does not work. The wiring at the relay is in terrible shape and appears to be connected incorrectly. I've looked at wiring diagrams and they show me what wires need to connect to the relay but not what terminals to connect them to. I don't see any markings on the relay itself either.

Attached is a picture I took a while back of the relay from a P14 that has been fixed up. I labeled the terminals in the photo with my best guess of how the wires should connect. Have I labeled it correctly? Also, does anyone know if the relay in the photo is mounted with the correct side up? Mine is mounted with the other end up.

I'd go look at the fixed up P14 if I could to see where the wires go, but I don't have ready access to it.

Thanks.

[Plymouthy Adams]

I is the ignition wire that is hot with key on run postion

G is the ground wire that runs through the column to the horn button energizing the relay

and makes the contact between H and B

B is the havy hot feed from the battery

H is the wire to the horn terminal...the horn itself must also be affixed with a good ground

your wiring does not look that bad....have you tested the circuit with the horn wire disconnected? doing this will split the system...for if the horn contacts inside are flakey or the horn is not proeprly grounded the circuit will never be complete...

take the horn wire loose..connect a volt meter/test light here...if you hit the horn button and it lights..suggest you test horn off the car..

the red Batter wire on the relay should be hot at all times...the Ignition wire is hot only with key on...the Ground wire can be shorted to ground anytime the ignition is hot to test for good path through the horn button..if it blows now then you have a bad wiring/button adjustment within the wheel center..the H wire is hot only if the relay energizes with the horn button...

[deathbound]

The mounting bracket has a hole on each side, above & below each hole, it tells you where each wire goes according to the terminal layout on the switch....ie: in the pic, above the hole on the right refers to the term on the top right, below the hole on the right refers to the term on the bottom right, & so on. Hope this helps. May need a magnifying glass to make out the marks on the bracket-sometimes they are stamped lightly.

[jcmiller]

Thanks Tim, that is great information that will come in handy once I connect wires to the relay. The shop manual also has some good tests. But I'm a step back from that, the wires on my relay are either disconnected or on the wrong terminals so I'm trying to figure out what terminals to connect the four wires to. In the picture attached to my first post, I labeled the terminals with I, G, B, and H based on my best guess at how things should be connected. Is it labelled correctly? If so, I'm going to rewire it accordingly and see if it will sound off.

Regarding the condition of my wiring, I wish mine looked like the picture! That was from a really nice '42. A picture of the disaster that is my horn relay is attached to this post.

[jcmiller]

Thanks. We posted at the same time so I had not read this before I posted my reply to Tim. I'll look closer for the stampings you mention. I see the IGN on the sample picture from the fixed up P14 but haven't found markings on mine yet. I'll look more closely. Jeff

The mounting bracket has a hole on each side, above & below each hole, it tells you where each wire goes according to the terminal layout on the switch....ie: in the pic, above the hole on the right refers to the term on the top right, below the hole on the right refers to the term on the bottom right, & so on. Hope this helps. May need a magnifying glass to make out the marks on the bracket-sometimes they are stamped lightly.

[Plymouthy Adams]

I was led astray by your earlier post of the very neatly wired relay picture...I now see the ugly truth you are dealing with...

regardless of the realy used be it a 3 post or four post..it will work the same way...and can easily be tested with an ohm meter to establish the correct position for the wires..

4 post realy will have continunity between one to yet another post..this is the pickup coil.. the other two posts will be open, but when energized will have continunity..this is your supply/load contacts..

remembering how the relay works will make wiring easy..key on to supply voltage to the energizing coil..other side of this coil through the horn button to ground...

12 volt supply to one of the other contacts with the horn connected to the other..

[Frank Elder]

.........

[Niel Hoback]

Here's a picture for you.

[jcmiller]

Wow, these horns are loud! I think my right eardrum is bleeding. Thanks for the help. I figured out the connections and can now replace the wiring so it looks more like the original picture. The tip about testing with the ohm meter, the diagram that Frankie posted, and reading a bit more about how relays work were the keys.

Once you figure out the H/B, I,G pairs, does it matter how you connect the wires? IE, can you connect the horns to H or B and the ignition to I or G? It seemed to work either way when I was messing with it, but I don't want to screw it up if it's designed to work in a certain direction.

I also figured out why the horn wires were disconnected (and maybe why the horn ring on the steering wheel is broken): I must have a loose wire somewhere, probably buried deep in the steering column, that is grounding the circuit out because the horn blows continuously once the G wire is attached.

...and can easily be tested with an ohm meter to establish the correct position for the wires..

4 post realy will have continunity between one to yet another post..this is the pickup coil.. the other two posts will be open, but when energized will have continunity..this is your supply/load contacts..

[greg g]

If you decide to try to replace the wire to the horn button, use the old wire to pull the new wire through. Probably easier to attach the new wire at the wheel, and thn pull it down from the steerig box end. That end of the wire should be fairly easy to find as it has a bakelite butt connector on it if its original.

Yep them are some loud buggers.

[Niel Hoback]

Ya oughtta hear 'em on a 12 volt Buick! Hooeeee!

[Brandon S]

I'm a little late on this one but going through the same thing- does the 'G' terminal which my replacement from Bernbaum has a female bullet post interchangable with the "S" terminal in the drawing diagram above.  My horns were missing and found an OEM pair on e-bay- no idea if they work but will deal with that later if needed to take apart.

[pflaming]

This is a good example of how the wiring is different in the cars a/g the trucks. The truck horn had no relay, just a direct wire from the regulator and had only one horn.  

 

My car is a 53 Plymouth, my truck is a 52 Pilot-house. 

[_shel_ny]

I'm a little late on this one but going through the same thing- does the 'G' terminal which my replacement from Bernbaum has a female bullet post interchangable with the "S" terminal in the drawing diagram above.  My horns were missing and found an OEM pair on e-bay- no idea if they work but will deal with that later if needed to take apart.

 

On the relay in this pic, all the terminals are identified on the two mounting tabs. (written very small)

 

Don't know what your relay looks like, but "G" goes to ground which is generally the wire going to the horn button which provides the ground and energizes the relay.

 

Power from the battery is at the terminal labeled battery waiting to continue on to the horns when the relay is energized.

 

Power to the terminal marked ignition allows for the horn to work only when the ignition is on. It could be wired directly from the battery if you want the horn to work with the ignition off. (caution there is to not connect any other wires to that terminal that you do not want to have power with the ignition off)

 

Last one is to the horn(s).

 

EDIT: spelling

 

EDIT 2: this is a 4104. The mounting tabs on other models may be labeled differently. Wire accordingly.

Edited May 12, 2013 by shel_bizzy_48