[T3] Invasion prep

[Gary Forsmo]

Whew .... Max & Jim.

I read both of your responses & came away with the feeling that (as you
said, Jim) ... the non-working horn is a v-e-r-y complicated issue.  And
may be fairly common.

And each of our cars MAY have one, or multiple failures in the
wiring/connection/modules.

After reading both of your entire messages my brain is "overloaded" with
the seemingly enless possibilities of where the problem may exist.

Max:  Thanks.

Jim:   Thanks for your analysis.  Now I  understand why you've never spent
time trying to track the "horn problem" on any of your cars.

I hope you can archive your comments for future reference.

Maybe when the weather improves and neither of us have a day when we have
nothing better to do (Haha) we can spend some time working on one of your
cars.  I can be your "second person" ...

If you're successful with that, maybe my car is next in line to solve my
non-working horn.

But I fully understand that each of our cars may have a completely
different problem.
---------
If you are scheduled to be a "presenter" at the 2026 Invasion in Eau
Claire, WI in June, would this be a possible subject for you to tackle?
-------------
Although much of Wisconsin is under Weather Alerts with double-digit, below
zero temperatures, we have appointments that require us to go out.  😆

Gary F. - Oregon WI

On Fri, Jan 23, 2026, 12:58 AM <jadney at vwtype3.org> wrote:

> On 22 Jan 2026 at 13:27, Max Welton wrote:
>
> > Jim, disconnecting the horn in this case means disconnecting the
> > positive wire at the horn.
>
> Good, this means that the problem must be IN the horn or in the ground
> side
> of the circuit.
>
> > The horn wire is connected as it should be. With everything connected,
> > the horn sounds when it should.
>
> Seems odd, but we may find out later why it's working this way.
>
> > If, however, I remove the ground strap from the battery, I measure 12
> > volts of potential between the battery terminal and the strap. This
> > goes to zero with the horn disconnected at the horn.
>
> Interesting test, good data. Following that lead, here's what you can test
> next. Put the + wire back on the horn and disconnect the brown ground
> wire.
> Measure the voltage between the - horn terminal and the brown wire.
>
> If you measure ~0 V, the problem is in the horn. In that case, you could
> remove both wires and measure the resistance between either terminal and
> the horn body. It should be infinite. I've never seen a horn problem like
> this,
> but anything's possible.
>
> If you measure ~12 V, the problem is somewhere in the ground circuit
> wiring
> between the horn and the steering column.
>
> In the latter case, I recommend that you measure the resistance between
> the
> disconnected brown wire and the body. If you have a second person
> available, have them watch your meter while you wiggle wires. They should
> see a change in resistance as you get close to the problem.
>
> > One thing to note is that due to the front beam being freshly
> > powder-coated I ran a ground wire from the steering box to the
> > chassis. Without that, the horn wouldn't sound at all. I've run
> > similar grounding wires for the rear signals and the fuel sender.
>
> There is an OE brown wire that jumps from the steering gearbox to the top
> bolt for the clamp that holds the beam to the pan horns (not the horn
> that's
> on topic here.) That wire is necessary not because of paint on the beam
> but
> because the rubber beam mounts keep the beam electricaly isolated from
> the body. Yes, if it is not installed, the horn won't work.
>
> If the horn checks out okay, there must be a mild short between the brown
> wire that returns to the steering column and ground. It's important to
> understand that there are two halves to the ground side circuit. The "hot"
> half
> runs from the horn up to the TS switch on the steering column. The "cold"
> side runs down the inside of the steering shaft to the steering gearbox
> and
> then to the pan (ground.) The horn button in the center of the steering
> wheel
> is what separates the two halves.
>
> The wire that goe down the steering shaft is not the problem, as that's on
> the
> "cold" (always grounded) side of the horn switch contacts.
>
> It seems likely that this brown wire, that goes up with the other TS
> wires,
> must be pinched or abaded somewhere. It's important to find it, because
> it's
> likely to be a full short eventually.
>
> The problem could also be in the horn switch itself. The horn contacts are
> part of the center of the horn ring at the center of the steering wheel.
> The
> horn ring is mounted/suspended by 3 shoulder screws with insulators and
> springs. Under each shoulder there should be an external star lock washer.
> If
> one or more of those lockwashers is left out, the horn will tend to honk
> randomly. It's also possible that if left out, there might be a poor
> contact
> there that drains the battery without sounding the horn.
>
> Sorry, this was long and, as I said, complicated.
>
> --
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
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