So I purchased an ‘98 Accord recently, but didn’t realize until after I was driving it home that it had a problem with the horn. It worked, sometimes–as long as the keys weren’t in the ignition, or the wheel was turned a little to the left or right.
After a few guesses and part replacements (relay, “clock spring” AKA “cable reel assembly”), I realized I was going to have to bust out the multimeter and really trace the problem. I figured out that the horn switch is supposed to get a ground from the steering wheel, and when the switch is pressed, it passes that ground through the cable reel assembly to the horn relay. It turns out that the ground on the steering wheel itself was intermittent. And it got its ground from the center of the steering shaft, which was also intermittent.
It seems there is a part of the steering shaft assembly that is meant to give electrical continuity to the center of the shaft from the outside shell. It’s a metal ring with small balls in it, but I don’t know the correct name for it. It looks like this is where the failure occurred. I understand it may be possible that the shaft became slightly bent from pressure on the wheel during an accident or a “panic stop”. That may have happened with one of the previous owners, but I don’t see any evidence of it.
Regardless, I filed a complaint with the National Highway Traffic Safety Administration, and if you’re experiencing the same problem, I’d encourage you to do the same thing. (I know of at least one individual who had an accident that would have been avoided had his horn functioned properly)
Meanwhile, I’ve found a temporary solution that seems to work well: grounding the steering wheel through an unused wire in the cable reel assembly. Shoot me an email if you’d like details.
As an aside, it appears that the ignition is a distractor in this case. When the keys are removed, an anti-theft feature causes a pin to lock the steering shaft, which happens to ground it. Since it should always be grounded by that ring anyway, it has nothing to do with the problem, other than causing a strange symptom. 
Found your articles and others very interesting.
I have the exact same problem, wth some exceptions:
1) Horn works very well when the out side temp drops be 20C, (heat related)
2) Replaced wiring harness, problem still there.
3) Once suggestion made was that inside the horn cover is a pencil like rod that all it needed is lubercating, as it was dirty, then the horn worked well.
Honda would not follow it up, because the horn was working at that time. Go figure !
This idea was not pursued by the Honda Service ????
4) This afternoon, I contacted the local Honda Dealership, and their answer was that the entire steering column has to be replaced. Over $1,000.00 ticket.
The problem I am having having is directly related to outside termperature. It is an intermitent problem.
Would appreciate your comments,
Cheers,
Orv.
Orv,
Assuming it’s not the horn relay, you probably have the same issue: the horn’s ground comes through the steering column.
Either you’ll have to pony up the cash to get a new one, or find another way of grounding your steering wheel. I used an “empty” signal line in the cable reel (aka “clock spring”) to route the ground through, but I think that “empty” spot was meant to isolate the airbag signals from the horn and cruise buttons. So there may be a (slight) risk that the airbag could accidentally deploy (or not!) from this modification, so it’s definitely at your own risk!
With the steering wheel covers off, bolts out, and airbag assembly out, you should be looking at the clock spring/cable reel. There’s a connector-looking thing on the front, with wire coming out of each slot, except one. That’s the one I used to ground my wheel. I jammed a wire in there, and the other end bolted to the wheel. Then, on the back side of the clock spring, there’s a connector where the cruise and horn signals leave from the wheel. One of the pins on that connector has continuity to the empty slot I jammed the wire in. I ran *that* wire to a good ground, and that resolved my problem completely!
Good luck.