I know what they are. What I'm saying is that the software updates for the car are often referred to as "firmware" by many people, whether they are technically correct or not. So I would not assume the Tesla person saying firmware actually meant firmware in the normal use of the word, they could have just scheduled a reinstall of the update.
If you need to barely press the wheel to get the horn to honk, that’s all but a guarantee it’s mechanical. The car has a simple switch for the horn like everything else, so it does not detect pressure. It has no way to know the difference between pressing hard or lightly, it just knows if the contacts are closed. The car cant sense axial load any other way.
The car has spoken...the problem was after all mechanical. You were right, ZOMGVTEK.
As I posted earlier, the problem seemed to be resolved with a reinstallation of firmware. About a week later the horn problem recurred, then went away long enough for me to get home, then became worse than ever. I called Tesla and got a mobile service appt two days later, long enough for the mechanic to get a couple of pieces of hardware he thought he might need (horn switch unit & steering wheel, I think).
The mobile service guy, Victor, was very good. He could not find anything obviously wrong and had to look for subtle things that might not be just right. Actually, the first thing he noticed was that, when he popped the airbag/steering wheel hub off, the horn gave a quick "toot," which he said was not normal. It took 45-60min, including a phone call to HQ to see whether anything like this had ever shown up on a Model 3 (it had not), before he said he was sure it was a bad horn switch unit. It was putting pressure on the horn button so that the button was tilted to the left and was only a hair from making contact even with no pressure on the button. What he initially noticed was that the gap between horn hub and adjacent steering wheel was less than normal. His idea was that a small temperature difference could cause a contraction or expansion of pieces that would bring the contacts together.
This could explain what I had experienced. The horn blowing began shortly after the car was delivered to us. It would have been riding on an open trailer so that when it sat in our drive for and hour or so, it could have warmed up or cooled down and presto! A week later when it started honking-upon-turn again as mentioned above, it was on a colder morning that it had been since we had the car. When I tried it again after several hours, the Sun had moved so it was in full sunlight, and there was no horn blowing. The next morning at home it was cool again, and more honking. All of this was subtle enough that it was not obvious, to me at least.
We had a trip of 1300 miles total beginning in a few days so I asked how confident he was of his diagnosis. Ninety-nine percent, he said. I asked, if his mother was going to take the car on a 1300-mile trip, would he let her go? He laughed. Then said, "Maybe, I don't know." I said, "But you said it was fixed? Why the hesitation?" "Well, there's that one percent."
We took the trip, no problems. While we were on the trip, Victor emailed to ask how Horatio Hornblower was doing.
During this whole affair I got nothing but the best of service from every Tesla person of which there were about eight.. I cannot recall any mechanic checking with me on whether their work solved the problem or was I satisfied. And I am 78 so that's a lot of mechanics.
I must say I do like the sound of silence.