Hello. For a few days now, I’ve been experiencing what’s shown in the video, with the car off, on, driving, stopped… https://www.youtube.com/watch?v=XEa5Md-r8uQ
I went to the Honda dealership in Bilbao and they aren’t sure either, they say it could be the headlight or the control unit, and that they would need to test with a donor car to know exactly what it is.
Has anyone had this problem?
Good afternoon, I couldn’t tell you what the problem is, but I can tell you that it’s better if your car doesn’t go through the Honda in Bilbao. 
I would try several things, the first being to disconnect the battery and leave it for several hours, carefully check all the fuses, and it would also be advisable to take a general look at the wiring you have access to, it’s not the first time a rat has caused trouble. Have you been touching anything in the car that might have caused this or did it start to fail all of a sudden? Has it rained a lot where you live or have you driven through any deep puddles? This is everything I can think of before taking it to the workshop. Let us know. Best regards🤘
The truth is, I don’t even know when it started, but I rule out the water issue because the car is always in the garage and it hardly rains. At the workshop, they disconnected the headlight, or so they told me… and I’ll check the fuses, but there’s nothing specifically for the indicator…
If it were an older car, I would tell you to take out the headlight and connect it to the wiring on the other side, at least to start ruling things out, but with today’s electronics, I suppose that can’t be done.
Hello,
I don’t write often, but I read you all very frequently. Thanks to everyone for the community and the support you provide. I have a 2020 Sport Plus and so far only joy with it.
I’m making my debut with a helping hand to our friend with this problem.
It happened to me about a year ago, and since it was under warranty, the Honda in Vigo changed the control unit. I had to make a video and send it to them to be believed.
Honda says it’s the MICU (a control unit located above the fuses, behind the steering wheel). The estimate to replace it is €1,900, and it’s something you can’t do yourself because this control unit manages the immobilizer and needs to be reprogrammed for your remote once replaced.
In all the cases reported in American forums, upon opening it, they discovered what appears to be water residue inside the control unit.
It used to happen to me, which is why I know all this. Now I’m in an observation period because it stopped happening when I stopped washing the car. Water can get in not only from rain; in fact, it’s quite likely that rain doesn’t let any in. I have my sights set on the sunroof and the A-pillar. Every day that passes without it happening makes me more certain it comes from there.
At first, I thought it was something I had touched, but when you start investigating, it becomes clear that it’s not. It’s not an endemic issue, but something causes this to happen in some units. Obviously, Honda is going to wash their hands of it, but notice that with three cases in the forum (and @Getit’s case, which was repaired under warranty), I’m considering sending an email to Honda Spain.
There are several documented cases on Reddit and the American forum. In fact, there are cars there that even had the alarm go off and the windows roll down in the middle of the night.
Do you have a picture of where that control unit roughly goes?
Above the fuse box under the steering wheel. If you look closely, you’ll see it; it’s the small control unit with all the cables connected. It’s this one:
Also, I should mention that the quote wasn’t exactly the same reference number as the one I had, so I understand that the control unit has been redesigned since it was installed in my car until the quote for a new one was requested.
Regarding what you mentioned earlier, does it only happen to those who have a roof, or to others as well?
The ones I know all happened to have a sunroof. One in Germany and another in the US, the rest didn’t respond when I asked them.
In this thread from an American Civic that has issues with roof sealing, it shows how the water ends up very close to the area of the control unit mentioned by @kermito
Since you have a sedan, you literally have the same roof as the Americans, (beyond the aesthetic design, I don’t know what differences there are between the panoramic sliding roof we have on European hatchbacks and the sunroof on sedans, which is the same whether in the USA or Europe)
It would be interesting to investigate a bit about cleaning the drains that these roofs have. I’ve climbed up with a ladder to look, but I haven’t been able to see where they go to clean them or to blow a jet of air to unclog them.
Here are some photos from the thread
But in that thread, it later mentions, upon solving it, that it was a problem with the sealing of the windshield on the lower part.
Morrillu: 
What will you tell me about what the lower seal of the windshield has to do with the roof fabric getting wet? It seems very strange to me.
Well, if you change the control unit and the water gets back in, what a deal we’re making…
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