Horn Relay Switch

[Tom Skinner]

Gents,

I have trouble keeping a Horn working. My other 1948 Chrysler Royal did not have this Relay, just a Horn Switch

There is a Relay (6 Volt) that was installed on my Chrysler when I got it back in 2007.

In this picture it Sits to the Left of The Horn Switch See Picture at Bottom with the S, B, H designation.

Can I re-wire my Switch without this relay, as it seems to burn out after about 10-20 Toots?

Tom

Edited September 1, 2021 by Tom Skinner

[desoto1939]

according to my autolite book the proper horn relay is HRL-4001 and the picture that you have posted is the correct Horn Relay.

 

Rich Hartung

 

 

[Tom Skinner]

Rich,

I will attempt to re-rout the wiring and eliminate the Relay to the Left.

I will report back this weekend and give results. (Its supposed to rain here tomorrow.

Thanks Rich.

Anyone else please chime in - I am not electrically talented

Tom

[LazyK]

I believe you have the photo labeled incorrectly or if that is how it is wired there in might be your problem. should have no reason for both 

get a wiring diagram for your car and trace the circuits out .

[Tom Skinner]

Lazy K,

Top Left (To Horns) is H

Top Right (Always Hot) is B

Bottom Left (Grounds @ Horn Button) is S

Bottom Right - No Wire 

This was an older picture from an older Post so That was the Labeling that came with it.

Tom

Edited September 1, 2021 by Tom Skinner

[LazyK]

I'm just going by what is shown in my Plymouth service manual. bottom two terminal should be reversed. Though in my thinking it should not make any difference as it is just a coil to energize the relay.

[Tom Skinner]

Lazy K,

Thank you!

Tom

[bamfordsgarage]

FWIW, the top photo in Tom’s original post was mine, labels indicate how the relay was wired when I purchased my D25 some 30 years ago. Horns worked fine for decades but a wiring fault elsewhere eventually caused trouble. 

[Tom Skinner]

I tried re-wiring to get rid of the Relay - no dice. That is to say routing wires directly to my Horn Switch.

I found my Horn Ring was bent badly after I took it off my Steering Wheel.

I straightened it, by bending it back slowly by hand. I re-wired that damned relay switch back up and the horn works fine again.

I wish I was a better electrician, and could figure how to eliminate that damned relay switch

Tom

Edited September 2, 2021 by Tom Skinner

[desoto1939]

Tom you need the erlay to energizse the horns the horn is from what I remember the point of grounding the horn and the electricity runs down the wire over to the relay to fire off the horns.

 

I might not be 100 percent on my explanation.

 

Rich Hartung

[Sniper]

You do not want to eliminate the relay.  The horn takes considerable current to function, the relay is rated to handle that current flow and the horn button is rated to handle only what is needed to operate the relay.  If you eliminate the relay and just use the horn button to operate the horn you'll be running all that current thru the button, which is not rated to handle it.  It'll pit/burn the contact points on the button.

 

Now, why do you want to eliminate the relay?  Might be another way to do what you want. 

 

 

[kencombs]

I had  typed an earlier reply very similar to Sniper's and failed to post it, it the wrong key I guess.  There is a reason why every maker uses a relay to sound the horn.  If you're not a purist, there are generic relays at every parts store that will replace it.   My 97 F150 must have at least 10, seats, horn, fuel pump, windows etc.  All exactly the same and interchangeable.  And none have failed since it was purchased in april 97, so they are not failure prone, very reliable!

[Pete]

Deleted.

Edited September 2, 2021 by Pete

[Tom Skinner]

Sniper,

OK good Thank you for clarification. I only wanted to eliminate it because I didn't see any on my first Chrysler Royal, or on any other 46-48 Chrysler's in my Chrysler Club.

No matter, as I tried to wire it up with out the Relay - Sparks flew everywhere, so I backed up and punted, and re-installed the Relay. The other thing I didn't mention from the beginning of my posts was the fact that the Horn would sound continually because of the bent horn ring on the steering wheel. Once I removed it and slowly bent it back straight, re-installed it, that solved that problem. It seems there is always something about these old Chrysler's that wants to act up. I have had to replace the Horn Relay every couple of years on this one. I am not a big horn blower, but I feel it should work, just in case, and as well as if they ever go to inspecting these old buses here in NC it would pass inspection. Right now Antique Auto's (Mine is Registered as such) in NC do not require inspection. I however make good and sure it is kept up to that level of repair by knowing the car is safe on the road. Well I guess that wraps up this Thread. Thanks again!

Tom

 

[greg g]

Relays are basically an electromagnetically operated switch.  Each one has two sides, the switched side , low Amp draw, and the power side, high Amp draw.  The power side is an open circuit at rest.  When energized a magnet draws a plunger closed to connect the load to power.  When the switched side is released the magnet shuts off allowing a spring to return the plunger ( some may have spring loaded points) to rest in the open position.  This allows a 15 Amp circuit to be controlled  by a 5 Amp draw through the control point. Many relays are self grounded, some like the hornrekay connect by a user activated ground connection for the switched side ie. The horn button.  The self grounded style needs a switched power run to energize the magnet.

 

 The load side it typically connected directly from the battery or a power distribution buss to the solenoid power side through the load which is grounded to the body.  This allows for a short run of stout wire which has minimal resistance through to the load.  The other advantage is these wire are an open circuit with no flow till the switched side is grounded.  So

 

Switch side is power in, through magnet coil, line out through user controlled ground.

 

Power side is batt in, line out to self grounded load.

 

[LazyK]

I think we have a communication, teminology problem here.

here is what I see

Toms first(top) photo shows a factory relay(tom calls it a horn switch)

second photo(botom) shows i believe Toms car with the factory relay and to its left an after market relay

The factory relay needs 4 wires to operate

The after market relay only has 3 wire. What appears as a power wire direct off the voltage regulator to the center terminal(B) and an added wire(since it is not wrapped in the original harness)to the left(S) terminal,  I can not see what is hooked to the right(H) terminal.

for an unknown reason a previous owner added the aftermarket relay. As wired the horm works any time you hit the horn ring on the steering wheel. When wired as factory the horn only works when the key is on

Again I say get a factory wiring diagram and a VOM(voltage ohm meter) and test/trace out the wiring. 

there is a possibility the factory relay was bad and the previous could not find a factory replacement. its operation can be confirmed using the VOM  

 

if Im wrong someone will correct me, that is the good thing of this site

 

[Tom Skinner]

Lazy K,

You are right, however, I do not have the Electrical confidence to correct this arrangement. If I find someone here willing to help me sort this out I will re-post.

Until then my only hope is my Electrical Engineer Nephew whom may be able to sort this out. I will repost if possible any developments.

Tom

[Sniper]

I am away from home today and tomorrow so I do not have my wiring diagrams handy, to be honest I don't think I am running a horn relay at all, my bad.

 

I think I figured out why the factory wired the horn to only work with the key on, more than once I have folded the driver's seat forward and honked the horn with the key in my pocket.  I might have to go back to the factory setup since it is dang loud running a 6v horn on 12v.

[Tom Skinner]

OK with more pictures:

Question where does the Battery Wire go? From the B Post to the Ignition Switch? Top or Bottom Post on the Ignition Switch?

Without anything Else the extra Relay read SBH.

Original Switch reads:

Top Left H

Top Right B

Bottom Left S

Where does the B Wire Lead to the Ignition Switch?

I give up, I am an Electrical Imbecile

 

Edited September 2, 2021 by Tom Skinner

[LazyK]

diagram does not show any horn wires connected to the ignition switch

my wiring diagram shows we are working with 3 green wires. and 1 red wire. unless someone has rewired the car and used different colors 

 

I've sent you a personal message

Edited September 3, 2021 by LazyK
wire colors

[kencombs]

As I read the diagram and pic, the top right (always hot) is connected to the battery terminal on the starter.  Top left (Horns) is connected to the horn wire.  Bottom left(Button) is connected to the horn button wire. Bottom right(Hot when Key on) is connected to the same terminal on the ignition switch that powers the coil.

 

With the 4 terminal horn relay that connection plan makes the horn able to be used with the key on or off.  Simply leavin the top right off will prevent it from working when the key is off.