Horn

[fordman]

i alwys wondered how the horn relay worked thats some good info there seattle 67.

[Supermike]

As Tow Mater would say... "Well, dang."

My $50 (incl. shipping) of horn replacement parts came from Carpenter today. For the most part, everything was a faithful match to the original. I bought a new horn brush/carbon, a new spring, a new pressure pad, a new retainer ring (the white-ish ring), and a new relay.

Put it all together, crossed my fingers, turned on the key, and...

I tried everything I had time to do... cleaned everything, and even cleaned down in the hole for the horn brush with a q-tip dabbed in alcohol. Nada.

So, as for seattle67's advice:

You may see + 12vdc there, but only if the horn relay is plugged in and the the coil in it is good. In that situation, you would be seeing the +12vdc that is going through your horn relay coil. (This would be a good thing as it means your coil is good)

Well, I'm not sure about that. I jumpered the two yellow wires with a tool that is like two pens with points, but one has a positive and negative light. When I jumpered those, the red (+) light came on. It did NOT sound the horns, though.

I tried putting my test light into the horn brush hole, but it did not work. I also hooked up my test light in place of the horns, but didn't get any light at all, so I don't think it's a low-voltage thing.

I also looked for a fuse... could not fine one anywhere. None on the fuse box are marked "horn", and I saw no in-line fuses under the dash.

The only thing I can think to do now is pull the steering wheel and check the contact plate to make sure it's wired. Can anyone tell me which wire that runs into the column on a 67 is the horn contact wire??

SO frustrating... I thought this was going to maybe be a simple fix.

[Supermike]

Anyone have any idears?

[kaptnkaos]

Hey Mike

Did ya check the horns themselves???
I did the following check on mine...

Seattle67 posted it my "more horn questions" thread

"Hi kaptn,

Yes, you can test the horns themselves just like you described, ground the body and pos 12vdc to the tab.

You can test the horn relay in somewhat the same way. On the relay there are 3 tabs, on one side there are 2 tabs and on the other side there is 1 by itself. The one by itself is the ground (lets call it tab 1), this is the one that gets the ground signal from the horn button. On the side of the relay that has two tabs, the one nearest the back of the relay is pos 12vdc input (call this tab 2), it should always have 12vdc + on it. The tab near the front is pos 12vdc output to your horns (tab 3). To test the relay, make sure you have 12v + at tab 2, then put a ground to tab 1. With that done, you should now see 12v + at tab 3.

To test your horn button circuit, put one side of your test light on the battery positive, and the other side put in the horn relay plug at the tab 1 spot. Have someone push the horn button, the light should go on when they do. If it doesn't, just start following the circuit towards the switch and look for the point that you have lost conductivity. It could be a broken wire, loose connection in a plug, or something funky with the horn carbon. It can be one or two of allot of things, so just go methodically down the line, don't jump around, and you will find it

Good luck kaptn!"

I found out that neither if my horns worked at all...
I got one from my bus and tried it, the system worked great...
I only have one horn at this point, but it works.
I got a set comin' but they have arrived yet...

Good luck...
Like Seattle 67 Said, be methodical... start at one plce and go thru the whole system and you'll get 'em working...

KaptnKA S

[Supermike]

Hey Kapn,

Thanks for the reply... I should have clarified, but my horns both work great. In fact, I just replaced both of them with "new" (to me) horns. Today, a wire runs from the fuse block to a button next to my choke, and then another wire runs from the button to the horn harness. So I have horns, just not from my horn ring.

The relay is brand new, so it shouldn't be dead. From advice here, I jumpered the two yellow wires and got juice (+), but it didn't make my horn sound off. I didn't do anything with the blue wire (with yellow stripe).

To test your horn button circuit, put one side of your test light on the battery positive, and the other side put in the horn relay plug at the tab 1 spot. Have someone push the horn button, the light should go on when they do. If it doesn't, just start following the circuit towards the switch and look for the point that you have lost conductivity. It could be a broken wire, loose connection in a plug, or something funky with the horn carbon. It can be one or two of allot of things, so just go methodically down the line, don't jump around, and you will find it

That's the part I'm facing now. I hope it's not a broken wire. I've replaced the carbon, but without pulling the wheel I don't know if somethign is getting in the way of the contact plate.

[SteveC]

i know at lwast on my 67 there was another carbon undernieth the wheel that was stuck pushed down in side of the wheel not making contact that caused my horn problem, i had to pull the wheel to fix the problem

[Underdog97]

There are 2 horn carbon brushes on the 67 to 69 trucks. One is on the turn signal switch and the other on the steering wheel itself. If even one of them are bad then the horn won't work properly. the blue wire with the yellow stripe is the horn wire on all turnsignal switches on 67 to 72 trucks

[ToughOldFord]

I'm not sure if this was on a Ford or not, but I seem to recall there being a metal strip that ran on the inside of the rag joint from each side of one of the bolt holes to ground the steering shaft. You could try a jumper wire to your steering shaft to test if it's a ground issue or not.

[Supermike]

There are 2 horn carbon brushes on the 67 to 69 trucks. One is on the turn signal switch and the other on the steering wheel itself. If even one of them are bad then the horn won't work properly. the blue wire with the yellow stripe is the horn wire on all turnsignal switches on 67 to 72 trucks

REALLY?! Does anyone have a picture of this 2nd carbon/brush? I only knew of the one on the steering wheel itself! Or is the 2nd one integrated into the signal switch?

I'm not sure if this was on a Ford or not, but I seem to recall there being a metal strip that ran on the inside of the rag joint from each side of one of the bolt holes to ground the steering shaft. You could try a jumper wire to your steering shaft to test if it's a ground issue or not.

You recall correctly... I did run an alligator clip (jumper) from my rag joint and grounded it to the frame. Would that work the same? If so, it didn't work.

THanks guys! I appreciate this!

[Underdog97]

both of the carbon brushes are the same

[kaptnkaos]

[ToughOldFord]

"A" is the wire that comes from your horn button. Like kaptnkaos says, it's open until you press your horn, then it supplies the ground to the horn relay. If it doesn't pass the test then there's a problem between that connector and your horn button.

"B" Should be constantly hot.

"C" gets hot when "A" supplies the ground to the relay and activates it.

If you run a hot straight to "C" and your horns do not blow then there's something wrong between "C" and your horns themselves.

There should NOT be current in the hole under your horn button.

[Supermike]

Thanks, fellas... I'll hit it with my tester tomorrow and run a jumper from my battery positive to "C" and see what happens.

Previously, I've put my test light in the spade adapter that the horn harness plugs into, and have jumpered "B" to "C" and have gotten a LIGHT on my test light. However, doing this with the horns plugged in does not cause the horns to blow. HOWEVER, I have not grounded "A" in the process, which means "C" would not have been grounded and hot?

I'll try to wiggle the wheel off and see what I can do there, too...

[Thunderfoot]

Here is a picture of the TSS Horn contact

click to expand

[seattle67]

Mike,
With the horns connected, putting a test light between "B" and "C" should light up the test light, but wont make the horns sound. Putting a jumper wire between "B" and "C" should make the horns sound.