Weird Horn Wiring

It's not hot. The horn is hot, the column is grounded. That's how it works-- you are completing the circuit by means of a ground. 

Stan Galat, '05 IM, 2276, Nowhere, USA posted:

It's not hot. The horn is hot, the column is grounded. That's how it works-- you are completing the circuit by means of a ground. 

Horn wiring depends on the column used. On the common 62-67 VW column, power comes from the fusebox, through the horn, and connects to the outer column housing. So the outer column housing is hot, the upper column bearing is hot, the column shaft is hot, and the steering wheel is hot. On the Beetle, they are isolated from ground by the rubber grommet at the firewall, the rubber sleeve at the upper column mount, and from the steering box by the rubber steering coupler. The button is isolated from the hot steering wheel by 3 small plastic bushings around the mounting screws. The ground wire runs from the horn button/ring, down through the center of the shaft, jumps over the steering coupler and connects to the steering box's shaft. Pressing the button connects the hot steering wheel to the ground wire and the horn sounds.

Because the whole assembly is hot, grounding it anywhere will also cause the horn to sound.

A picture helps -

justinh posted:

Stan Galat, '05 IM, 2276, Nowhere, USA posted:

It's not hot. The horn is hot, the column is grounded. That's how it works-- you are completing the circuit by means of a ground. 

Horn wiring depends on the column used. On the common 62-67 VW column, power comes from the fusebox, through the horn, and connects to the outer column housing. So the outer column housing is hot, the upper column bearing is hot, the column shaft is hot, and the steering wheel is hot. On the Beetle, they are isolated from ground by the rubber grommet at the firewall, the rubber sleeve at the upper column mount, and from the steering box by the rubber steering coupler. The button is isolated from the hot steering wheel by 3 small plastic bushings around the mounting screws. The ground wire runs from the horn button/ring, down through the center of the shaft, jumps over the steering coupler and connects to the steering box's shaft. Pressing the button connects the hot steering wheel to the ground wire and the horn sounds.

Because the whole assembly is hot, grounding it anywhere will also cause the horn to sound.

In other words, is what I'm experiencing is normal? 

Would someone else please try it on their car and see if it happens? Thanks.

@wombat - Mine is wired the same and operates the same as yours.  If I ground the steering wheel, shaft or housing, the horn will honk.  Typical VW wiring for mid-60s.  Justin's explanation is accurate, along with Wolfgang's picture.

James posted:

@wombat - Mine is wired the same and operates the same as yours.  If I ground the steering wheel, shaft or housing, the horn will honk.  Typical VW wiring for mid-60s.  Justin's explanation is accurate, along with Wolfgang's picture.

Thanks for trying it out and confirming that my car isn't ready to zap me. 

They did eventually get around to correcting that flaw. 68-70 the outer housing is no longer hot, 71+ nothing is hot.

Yeah, it took me a while to figure that out on my '69 column.  Finally got tired of rebuilding my jerry-rigged setup every other year and decided to make it "right".   Took almost a full afternoon to figure out what was going on and making it work properly with an isolated column and insulated top bearing.  That was three years ago - Maybe I'm about due?

Justinh is correct, at least that is how it is on Vintage and JPS cars, I'm not sure about any others.  I ran in to this a few years ago and posted about it, because it just didn't make sense to me.

That's really, really odd. 

I have the same setup as Wombat on my VS built car. I've changed the steering wheel to a Derrington with a MOTO-Lita compatible hub. On my previous setup I had a Grant five-bolt wheel with a very small all plastic horn button. On the back of the horn button are two tabs for solderless connectors. There was an orange wire (non-powered) coming out of the column and onto the tab in the center of the horn button. There was a black wire coming from a solderless connector attached to a bolt in the hub and it had power. That wire went to the other tab on the back of the horn button. This tab was out near the edge.

After I installed the new hub and wheel I checked and the metal parts of the wheel have power so I removed the black wire that was attached to the boss.

My new horn button only has one tab in the center of it on the back. I attached the orange non-powered wire to it. I assumed that the horn button when inserted into the hub would complete the circuit but it would be an open circuit if the horn button were not depressed. I further assumed that pressing the horn would complete the circuit and honk the horn but I was wrong. I press the horn button and nothing happens. However if I touch the tab that the orange wire is connected to to the steering wheel the horn honks. If I depress the horn button nothing happens.

I took the horn button out of the hub and made sure the metal ring of the horn button was touching the metal parts of the wheel and it still didn't honk when I depressed the horn button  

Is the horn button faulty?

I doubt it.  Sounds like it is just completely isolated from the rest of the steering wheel.  Check the continuity from the pin to the outer edge of the button. 

Troy Sloan posted:

I doubt it.  Sounds like it is just completely isolated from the rest of the steering wheel.  Check the continuity from the pin to the outer edge of the button. 

I will do that. There was a brass tab on the back of the horn near on the outside edge of the horn and I even tried to touch that to the steering wheel to make it honk and no luck there either.

I will check the continuity between the post/tab and the outer edge of the horn and the brass tab.

I've tried and failed at my horn setup. I'll deal with the horn AFTER I get Eleanor on the road. I'll carry a hand-held air horn in the mean time 

I stole this photo from the internet but it is the exact same horn button:

My assumption was that the orange wire coming up from the steering shaft connected to the brass center post. There is a small allen bolt that backs out and you secure the wire by tightening it up after inserting the wire. Then my assumption was that the brass tab (right side of the photo) came into contact with the side of the hub and when the horn was depressed it would complete the circuit.

I put one lead from my continuity tester on the center post, depressed the horn button, and touched the other lead to everything on the horn and could not find anywhere that completed the circuit.

The small hole in the left side of the photo is where a small plastic post pushes through when the horn is pushed. It appears to be to keep the front of the horn from spinning in a circle.

Where is @Trevor P.? He just did this and I'd like to hear from him?

If you touch the two wires together you get horn, right?

If so, you're going to want to connect the wire that comes through the shaft to your horn button, and the orange wire to the post. (I think). The button should have some provision for the black wire, and when you press it, it should hit the brass thing, completing the circuit.

edsnova posted:

If you touch the two wires together you get horn, right?

If so, you're going to want to connect the wire that comes through the shaft to your horn button, and the orange wire to the post. (I think). The button should have some provision for the black wire, and when you press it, it should hit the brass thing, completing the circuit.

The old horn button had two tabs. The orange wire coming from inside the shaft went to the center tab and a black wire was attached to the inside of the hub and went to the second post on the back of the old horn button. I determined that this was because the old horn button was isolated form the metal parts of the steering wheel and would not close the circuit when the horn was pressed. By building an open circuit inside the horn the circuit would be closed when the horn was pushed but the hot lead had to be connected to the back of the old horn button.

The steering column, boss, hub, and wheel are "hot" and if I touch the orange wire to any of these metal parts the horn honks. The new horn button has a brass tab that sticks out a little and comes in contact with the steering wheel hub and gets power from the hub. The orange wire connects to the brass post in the center of the new horn button. My assumption is there should be an open circuit between the brass tab and the brass post that closes when the horn button is pushed down causing the horn to honk. The circuit is "open" as long as the horn isn't pushed. As soon as the horn button is pushed it should in theory close the circuit and make the horn honk.

None of that happens and nothing I do will make the horn honk. I have tried a wire from the hub to the brass tab and the orange wire to the post. I have touched the brass tab directly to the hub. And all manner of other variations. No horn.

Does the button say 'Lucas' on the back?

Troy called me after my last post to offer some help. He went out to his new Speedster shop and found a spare horn button identical to mine. He put his continuity tester on the center post and the brass tab, pressed the horn button, and found he had no continuity either. Bewildered by this he messed around with the horn button and got repeatable results with positive continuity. 

What did he do you ask? He spun the brass center post in circles a few times and moved the horn button side to side every so slightly since it is not designed to spin. For whatever reason that made his horn button work.

I'll do that to mine. Meanwhile I've contacted the seller on eBay to get me a new one. For $178.00 the horn button should work right out of the box.

Robert,

These new horn buttons are cheap. Press too hard and the connectors inside bend then the horn won't work. Take the thing apart and you will immediately see what I'm taking about. Bend the connectors back to an operational state then go easy on it when depressing the horn button.

Also, a new one out of the box will have at some point the same issue so you may as well learn how to fix it now. Be careful when taking it apart as the tin is very cheap Chinese pot metal and will break.

Yup.  I broke one of the tabs off of mine! 

356Devotion has a similar horn button and that seller told me the horn button he sells has a stainless steel outer ring and that they are made in Portugal Europe. The photo of the horn looks exactly the same as what I have now but there's no way the outer ring is SS. And the horn 356 Devotion sells is $238. 

Wow. I'm glad more knowledgeable heads chimed in.