Horn went silent

[White Spyder]

My horns have quit working.  A few years ago I re-wired the engine bay with a kit from Rhode Island Wire. The car is still POSITIVE GROUND. I think my first step in diagnosis is to eliminate the horn relay. To do this I was thinking that I should take the wire coming from the steering column where it connects to the harness with a bullet connector and use a lead to touch to the negative terminal of the battery and see if the horns activate. 
 

Am I thinking correctly?

[Plymouthy Adams]

not if you positive ground....the wire to the horn button grounds the relay......

[White Spyder]

So, touch the jumper lead to the POSITIVE terminal?  I hate electrical issues!

[White Spyder]

Tested the horns with a jumper from the NEGATIVE terminal and they work. With the jumper from the wire coming from the steering column, I get a click at the relay in the center of the photo but nothing from the horns. When I press the horn ring on the wheel, I don’t get the click at the relay. 
 

Bad relay?
 

 

[White Spyder]

Bit mor info. The photo below is of the relay I removed. It has 4 terminals and they are marked with the letters H, B and S.  The one marked S appears to have two connections. 

Burnbaum’s has a relay listed for my car but it has only 3 terminals and appears to be a universal horn relay.  Anyone have an idea on the part number for the 4 terminal relay?  I cleaned of the paint and found no part number on the one I removed. 
 

TIA

 

 

 

Edited July 17, 2022 by White Spyder

[joecoozie]

Possibly a bad ground

[slatgrille]

Replaced a relay for my P15. Part 'S' had broken insulation. I found a 4 contact unit on e-the-bay that was NOS. I believe the letters stand for H=horn, B=battery, and S=solenoid. The 'bullet' connector was for the wire from the steering column.

 

I'm new to the early MOPAR world, so I could be all wrong....just offering what worked for me.

 

Craig

[Kilgore47]

Take the relay you have apart to see if you can fix it.  May just be a corroded contact that can be cleaned.  As stated above - check the ground first.

[White Spyder]

Cleaned the terminals, back of the relay and the fender wall to make sure ground is good. Opened the relay and it appears to be intact. The lower terminal S has power constantly the upper one the rest are zero volts without the horn button pressed. When the ground wire, upper S bullet is jumped to the POSITIVE ground, the relay clicks but the horns do not activate. 
 

any helpful suggestions?

[LazyK]

With a meter or test light you should have power on the B terminal all the time and power on the S terminal only when the key is on.

simple test

take a test lead and connect it to the negative terminal of your battery touch the other end to the H terminal, it the horn works you have determined the horn and the wire from the to the relay is not the problem.  

second remove the test lead from the - battery and reconnect it to the positive terminal (ground) on the battery, touch the other end to the round (bullet) connection on the relay if the horn sounds your problem is between the relay and the horn button on the steering wheel. if the horn does not sound then you have a bad relay. Key must be on to perform this part of the test

 

Edited July 19, 2022 by LazyK

[White Spyder]

Been traveling for work. 
 

keep in mind that I have not moved any wires since the horns quit working correctly. 
 

key off, with a volt meter, I get nothing when grounding to the battery at the B terminal. I do get 6.4v at the S terminal. 
 

Key on, I get 5.8v at B terminal and 6.4v at S terminal. 
 

grounding at the battery, I do not get horns activated  when touching the test lead to H. 
 

 

[SteveR]

Do you get any voltage at the horn?

[greg g]

Is the wire that goes into the steering box connected? There should be a phenolic connector  in line, going from the relay up through the box column to the button. Make sure there is a good clean connection  there.  It doesnt take much corrosion in these conne tions to cause a problem.   Also I have found the bolts mounting the horns to their mount need to be good and tightly screwed in.

[LazyK]

looking at your original post it looks like you have a "fork" connector inserted where a "bullet"  connector is required.  I would guess it had developed corrosion and it not making a good connection

[White Spyder]

Work has kept me from following up on the horns.  Here is the latest information

·         Continuity tested good from:

o   Connection out of steering column to both S terms on the relay.

o   Connection from H term on the relay to the horn.

o   Connection from B term to the voltage regulator.

·         Using a jumper from the connection out of the steering column to the S bullet term on relay does not activate horns or relay.

·         Jumper from S bullet term to ground (positive ground) on battery the relay clicks.

·         Jumper from the negative battery post to horn sounds the horns.

·         With the key off or on the horns do not sound.

·         Replaced relay (found one local and cheep) no different results.

 

Questions:

o   On the relay, S term, where does the non-bullet wire go?  I want to check that continuity.

o   Should there be continuity between both the S term connections?

o   What voltage should be going to the B term on the relay with the key on and off?  

o   What am I missing?

[White Spyder]

I know that trouble shooting the horns should be simple but I must be missing somthing.  Does anyone have the scmatics of the horn circuts?  

 

[Sniper]

No idea what you are working on

[Los_Control]

My first thought were to check that the horns actually work

Next would be connections.

Then I would go into the horn button.... remove the horn ring, unplug the horn at the exit point out of the steering column ....

 

I would tie string onto the wire while pulling the horn ring & wire through the column so you can inspect it on the work bench.

 

My truck does not have a horn ring .... just a horn button in the middle of the wheel.

The wire where it exits the column .... mine was in pretty bad shape with the wires bare from rubbing the insulation off.

The horn button the wire passes through a metal plate that is held in place with a snap ring. I do not know whats on the other side because it is all enclosed.

 

I just know I will need to take it apart and replace the wire & clean all connections there before I put it back together.

 

I saw in your photos what looks to me as if your car was rewired with modern cloth wiring .... did they also replace the wire from the horn button out the steering column?

[White Spyder]

16 hours ago, Los_Control said:

My first thought were to check that the horns actually work

Next would be connections.

Then I would go into the horn button.... remove the horn ring, unplug the horn at the exit point out of the steering column ....

 

I would tie string onto the wire while pulling the horn ring & wire through the column so you can inspect it on the work bench.

 

My truck does not have a horn ring .... just a horn button in the middle of the wheel.

The wire where it exits the column .... mine was in pretty bad shape with the wires bare from rubbing the insulation off.

The horn button the wire passes through a metal plate that is held in place with a snap ring. I do not know whats on the other side because it is all enclosed.

 

I just know I will need to take it apart and replace the wire & clean all connections there before I put it back together.

 

I saw in your photos what looks to me as if your car was rewired with modern cloth wiring .... did they also replace the wire from the horn button out the steering column?

Yes that was replaced.  From the thread, I can get the horns to blow when jumping them directly with the battery.  I can not get them to blow when grounding the wire from the column to any point on the relay.  I do get the relay to click.  new relay since this started too just to be sure.

 

[Los_Control]

35 minutes ago, White Spyder said:

I can not get them to blow when grounding the wire from the column to any point on the relay.  I do get the relay to click. 

Horns & relays are a big mystery to me. Just throwing out ideas.

Seems the horn gets power from the relay, pressing the horn ring makes the ground & complete the circuit for the horn to blow.

 

So just touching the wire to the relay should not complete the circuit without pressing the horn ring at the same time .... maybe you did this?

I have a long wire with alligator clips on the end I use for testing things.

 

You tested the horns and know they work, I would use my test wire from the column to the horn bypassing the relay. Then test your horn button is making contact & it works.

Wired this way the horn should activate when the horn ring is pressed.

 

Again a truck horn button would be different from a car but I think the principle would be the same.

Inside I would expect to to find a spring holding the horn button out, two brass or copper contact plates. The wire would be soldered in some way to a brass contact plate ..... There is a few potential failure points here.

The horn button is a simple electrical switch & need to verify it is working.

 

 

 

[moparfun]

Just got the horn circuit working on the Plaza, so have you disassembled your horn ring at the steering wheel and cleaned all the contacts?  Sounds like your wire in the column may need to be replaced.

[White Spyder]

In the photo below, I have unplugged the wire from the column and jumped the green wire to terminal S on the relay with no sounding of the horns.  This bypasses any question of the horn ring on the steering wheel.  Something else in not right.

 

 

[DJ194950]

Ground the green wire to the body or frame/battery positive if still pos. ground.

 

anything?

 

DJ

[SteveR]

You should have 12vdc to the relay when the horn ring is depressed. If not then see if you have 12vdc going to the horn ring.

If yes then check to see if you have 12vdc coming to the contacts of the relay. If yes then you should have 12vdc out from the contacts to the horn.

 

The horn ring will close the contacts of the relay allowing voltage to go to the horn.

 

What car is this out of?

Edited August 12, 2022 by SteveR

[White Spyder]

Car is still 6 volt positive ground.  1948 Chrysler Windsor.  Jumping the green wire to the ground on the battery gets only a click at the relay, no horns.  That green wire goes to terminal "S" on the relay.