On road rage

Okay, so the horn on the bus has been…lacking at best. One of the reasons for this is VW’s godawful, stupid, mind-bogglingly dense setup for how the horn works. I won’t get into too many details, but the short version is: the entire steering column, from the bottom mount to the top mount, is isolated from the rest of the vehicle. Towards the bottom of the column, there is a riveted/welded on spade connector, and a jumper wire is strung down AROUND the steering junction (that has the gubbin/rubber biscuit, also a part of the isolation system) to a steering box bolt. At the top of the column is the horn ring, and a wire runs UP THROUGH THE CENTER OF THE STEERING SHAFT, coupling to the horn button. Pressing the horn button (which is isolated with 70’s era plastic spacers, mind you) shorts the center wire with the outside of the steering column, which has a second jumper wire that is run down to the horn.

So, the horn is live all of the time, and the ground for the horn takes a convoluted pathway up through the outer steering column, across the horn button, and down the central wire to a bolt on the steering box (around the spinning steering components, as well.) Everything else on the column, like the ignition barrel, wiper switches, and turn signal switches, is isolated from the column itself (because all of those components are grounded) with various bits of 40-year-old plastic. Also the wire that runs down the center (that twists when steering) can rub through the insulation and short on the inside of the column, or the button ring can get dirty, or a previous owner (:argh: PO’s!) could use a self-tapping screw in the wrong spot. The chances for problems with this setup are crazy, and could have been solved with one simple slip ring.

You know that scene/theme in Little Miss Sunshine where the horn starts going off and won’t stop for the entire rest of the road trip? It was funny because buses were ubiquitous in the childhood of adults today (and, well, grandparents today), so their common problems, like the horn, were equally part of the public consciousness.

Well, mine has been off-and-on doing the same thing, along with just plain not working when I wanted it to. I removed the button and cleaned and re-adjusted the spring tension, but nothing was working. The only fixes I find by looking at the diagrams and reading online necessitate removal of the steering box and column, because the column comes out from the bottom.

Fuck. That. Noise.

Make louder, better noise.

I’ve been planning a horn upgrade like I did on the beetle for a long time, and at the same time I’ve been scouring ebay listings. I found two things on the cheap that are going to make my life so much better (or, conversely, get me shot). One of them was a used (but guaranteed functional) Carson HA-100 electronic airhorn amplifier. I wanted to stray away from what I did with the beetle (buy a used siren headunit), because technically installing a siren, even if you don’t use it, is illegal in many states. Also, a siren headunit is large and takes up valuable underdash space. Also, I planned on mounting the amplifier behind the bumper in the crash structure, and it is a lot easier to waterproof (read: fill with silicone) a small amp. Also they are a lot cheaper so if it breaks (and is unrepairable because I have filled it with silicone or sprayed conformal coating on everything) I’m not out bank.


My install is ugly as sin, but you’re going to have to trust me on this one. Also, all pictures are before final wire-tying and grommeting. I want to drive for a day or two to be sure everything stands up to vibration and works before I commit.


While I was down there, I took note about how every new part I’ve put on still looks amazing. Thanks, Arizona!


Along the way, I have become a full convert to Wago Lever-nuts. They are UL listed and approved for junction box use, and they hold onto the wire tighter than anything I have ever seen, while still being re-usable. They are about $.30-50 apiece, which is spendy for home use, but I think it’s worth it in a vibrating automobile.

Ignore the loose wires. Those are unused from the “harness” I ran a few months ago.



“But Geir, what are you going to use for the horn button? You already said the column setup doesn’t work!”

Don’t worry fam, I got u covered

A drill, followed by a razor blade trim, please.


Plus some 3D printed magic (seriously magic, I went from concept to prototype in less than two hours)


(Those are stainless screws)

The purple one is a concept. I’m going to splash some water on it and see where it collects, and modify the .STL file to add a drain hole. Don’t want any water collecting.


Edit: I should add that the shit ground and the blue->black wire change is intentional, before anybody asks. The bus is getting a full re-wire next summer with my Motogadget M-Unit V2 that I’ve had sitting in a box for over a year. And I need to pick up more ring terminals.


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