Horn

[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.

[ToughOldFord]

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.

Exactly, and you wouldn't need to ground "A". When you are jumping "B" and "C" you are bypassing the relay and the horn button by suppling power to the horns directly. If jumping "B" and "C" doesn't sound your horns and you checked that "B" is hot then you have a problem in the wiring between "C" and your horns. (My first check then would be the horns themselves and their ground, but I see that your are working when wired directly so that just leaves the wiring)

[Supermike]

Thanks for the picture, Thunderfoot!! Although I'd hate to have to pay shipping for a single horn brush (can you get those at a dealer? Anyone know the official part #?), I'm really hoping that's all that's missing.

I have two kinds of test lights. One looks like a scratch awl with a light in the handle and a thin wire with an alligator clip for grounding. The other looks like two pens with points, with a wiring running between them, and two LEDs on them. One is (+), the other is (-).

So, using the awl-type light, I put it in the spade adapter where the horn harness plugs in. I then used the other tester (a jumper?) to cross "B" and "C". It made the test light at the harness plug light up, as well as the (+) on the tester. HOWEVER, after removing the test light and plugging in the horns, it did not sound the horns. Why would it light the tester, but not sound the horns? And is my "two pen" tester really a "jumper", or do I need to use something else?

Thanks for the continued help. Just trying to be careful here... don't want any magic white smoke like Capn K got.

[kaptnkaos]

Hey Mike...

To test the horn button relay you wanna jump "A" and "C" with the test light... if the test light comes on when you push in the horn button then that circuit is good.
If it doesn't come on then you know that circuit A (horn button) is faulty.
It doesn't necessarily mean that that the horn carbon it self is bad.
I could be a bad connection or broken wire in that circuit.
If the horn carbon is intact, it might just be dirty/corroded cleaning it up with some emery cloth will fix that. It could also be the contact plate on the steering wheel... they also get dirty. You can clean them with the emery cloth as well.
I would also recomend putting some di-electric grease on the contact plate and tip of the carbons (both). That helps lubricate then and keeps them from corroding. It is inexpensive and you can get it at any auto parts store.
You don't have to put very much of it on, just a very thin coating.
Because it conducts electricity it can cause electrical contacts to bridge and create a short...
I use this stuff on light bulbs and on any other kind of connector or plug, making sure that I don't bridge any of the contacts with it.
It's the same stuff that comes with a points set and many other electrical things that require lubrication.

I tried to copy a schematic of the horn circuit so I could post it for you, but it is on a protected disk so I can't copy it.
I can however, print it out and scan it this evening when I get home, then I can post it as a jpeg.

Electrical gremlins can be a PITB, but with patience, they can beaten.

KaptnKA S

[Thunderfoot]

Hey Supermike,

Not sure on your two point tester... but it may not (probably not) allow enough current through for the horns to work but will for the test light... Take a small piece of wire and strip the ends and use it to jumper B and C and see what happens... If your horns still don't work then try using that same piece of wire to jump between the (+) battery and the "C" and see if that works. If that works then check the yellow wire from "B" that goes to the starter solenoid and make sure it is ok and making good connection. Here is the wire diagram for the horn if you haven't seen it already... http://www.fordification.com/images/sch ... ircuit.jpg There is no Fuse for it...

If the jumer wire worked then do this to check the rest.

To Check your connection / operation of the horn button on the steering wheel you can use either one of your test lights. For the awl-type, clip the alligator clip to the positive on the battery and stick the awl end in the "C" on the relay harness. Then go inside and press the horn button down, the light should light up! if not then you have a problem from the horn button to the relay.

If this is the case, then to narrow down where the problem is take and unplug the TSS under the dash (bottom of column) and take that jumper wire you made up and put it on the "Blue-Yellow striped" wire in the truck half of the harness and ground it. This should make the test light - light up (or the horns work if you plugged them back in), if not then there is a problem with the wire in the dash to the relay...

If that works you can double check the horn button wiring in the TSS by taking your awl-type test light and connect the alligator clip to power on the fuse block and put the awl end on the "Blue-Yellow striped" wire that goes in the column and press the horn, this should make the test light - light!
Also, with it set up this way try taking another piece of wire and ground the steering shaft out by the coupler to be sure you are getting a good ground there.

See where all that gets you and let us know what you find.

On the Horn Carbon Brush you should be able to get this at the dealer... If you have a good NAPA parts store they might be able to find it also...

[kaptnkaos]

Right on TF...

That's the same one I was gonna scan and post this evening...

I have the whole set of '68 service manuals and wiring diagrams on disk.
But they won't let me copy them.
I can however print them out then scan them.
I also have the full set of the original hard copy manuals.
I bought what was supposed to a complete hard copy of the wiring diagrams, but a few of the pages were missing, but now I can fill in the gaps... Yes !!!

KaptnKA S

[Supermike]

THanks guys... I'll try to dig into it some more tonight and try out your suggestions.

I actually have a full set of '67 service manuals, but unfortunately they don't have much info on the horns.

[Supermike]

UPDATE:

Thanks to your help, I've made a little progress tonight!

1. I made a jumper from 12g wire with spades at each end. Figured it would come in handy in the future. Jumpered "B" and "C", and promptly wet my pants when the horns sounded! Conclusion: wire/harness from relay to horns is FINE, and I don't want to do that again.

2. With lots of slight jiggling back and forth of the steering wheel, I finally removed it -- no puller necessary. What I found underneath was a load of nasty gunk AND the horn carbon/brush in two pieces (only one of which was in the hole). I cleaned everything up with qtips and alcohol, and inserted the new carbon I had just bought. I also removed the contact plate and cleaned it up good (it was cruddy).

3. I then adjusted the turn signal cam slightly (in hopes that it will now shut off my left blinker), and put the wheel back on and the horn back together.

That's where I've left things for now, as I'm out of time to do more tonight. I'm fairly convinced (aka hoping) it is/was the broken horn brush/carbon and gunk build-up that was causing the problem. My mission tomorrow is to try and find a carbon in town at a dealer so I don't have to pay $8 shipping on a $5 item!

[kaptnkaos]

Right on Supermike ...

Yep, I bet that was yer problem...
If I had an extra one I'd send it to ya...
I had one a couple of weeks ago... but ended up having to use it
I dropped one somewhere and lost it... believe me, I looked everywhere for it.
The spare one I had was pretty rusty, so I cleaned it up wih some steel wool and emery cloth, and put some di-electric gease on it and it worked... yes !!!
Have you checked at any of the local hardware stores???
Most of them carry carbon brushes all you need is one that's the same side, they're all pretty much the same.

KaptnKA S

[Supermike]

I called to a local Ford dealer this morning, and he didn't have any horn carbons but a dealer about 45 miles away did. I called them and they had three. Said the list price was $13.10, but would let me have it $9.95ea plus $5 shipping.

I said no thanks... I can order one from Carpenter for $5, with $8 shipping. Oh well.