'98 Accord horn - WEIRD electrical problem (simple solution? ground?)

I've got a '98 Accord with a really weird problem. The horn is
intermittent while driving (it doesn't work when the steering wheel is
centered, only when turning). When the engine is shut down, and the
key removed, it works perfectly, no longer intermittent. When removing
the key, it's after the very last "click" that the horn starts working
correctly. First, I tried replacing the cable reel assembly, which
didn't make any difference.

Now I'm trying to troubleshoot the circuit, but my dumb Haynes manual
doesn't have anything in the schematics for the horn. Does anyone know
what the source is of the signal for the horn? There's one wire coming
out of the airbag assembly (where the horn switch is), and it has a
ground when the switch is pressed. Which ends up actuating the relay,
etc. But where does that ground come from? I think that's where my
solution lies. I thought the ground might come from the SRS wires, but
nothing changed after disconnecting them. Same with the ignition
switch.

I just can't understand why the ignition switch would have anything to
do with this problem, since the horn should always be hot!

Any suggestions or ideas would be welcome!

 

Just a wild guess, but if you have a bad ground for that portion of
the wiring harness (or the whole car), the circuits that are on with the
key may be 'using it up' and leaving the horn with an inadequate ground.

 

It may not have anything to do with your problem, but did you
have the recall done, to replace the ignition switch? It caused all sorts of
weird problems!

 

No, it was never done on this car, but Honda of America said my VIN
wasn't affected.

 

On Jul 10, 12:36 am, wrote:

Well, I think I understand now. It looks like the horn switch gets its
ground from the steering wheel, which is grounded via the steering
shaft.

It *looks* like the steering shaft itself is supposed to be grounded
by the ignition switch, which isn't doing its job. The outside, the
steering column, is grounded perfectly, but the steering shaft is
intermittently grounded, depending on the position of the ignition
switch. I've also noticed that just wiggling the key while it's
inserted in the ignition will cause the ground to come and go.

I just wish I could figure out an alternative to replacing the
ignition switch! I can't even get it off right now, since I'm on a
road trip and have limited tools. (no drill) I tried running a
grounding wire to the steering wheel, which works, except for the
safety issue of having a wire attached to a steering wheel, getting
tangled, etc.

Does anyone know of a way I could ground the *inside* of the steering
shaft? The rack end is sealed and lubricated on the inside, right? So
the only way/place I could do it would be the exposed end at the
wheel, or where the ignition locks the shaft, right?

Thanks for any suggestions!

 

The fact that your problem only occurs at certain positions of the wheel
suggests that it may not be the switch (though it's still possible).
Based on all other horn systems I've seen, there's a wiper that travels
with the steering wheel and makes contact with a fixed annular plate on the
column. It's supposed to provide a path from the horn button to the relay or
chassis. It may be a brass or bronze strip, a spring, or even a carbon
brush. You may just hear it as you turn the wheel. If it gets dirty, it may
no longer be making contact with the grounding plate.
Radio Shack sells a pretty good contact cleaner as a spray pack with a
selectable bristle brush or fine tube. Squirt some of that stuff behind the
steering wheel, between the wheel and the top of the column (probably hard
to get at) while you're turning the wheel from side to side. Use a lot of
it -- it evaporates and probably won't hurt anything except perhaps your
lungs. Leave your windows open.
If you can't find contact cleaner, silicone lube from your local
hardware store or auto parts place works reasonably well. Use less; it
doesn't evaporate.

Pete (fP)

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