TL;DR: I hit the "Adjust Headlights" button on my Model 3 last night, and now the headlights have been stuck on ever since. So far Tesla doesn't know the cause or how to fix it. Bottom line: I'd recommend no one else touch that button. (I'm on firmware 2018.28.5.) Full story: Last night while parked I hit the "Adjust Headlights" button under the Service menu just out of curiosity to check it out the functionality. An "Adjust Headlights" window popped up on the screen, but all the buttons were grayed out and there was just a circle spinning around and around (like when you're waiting for something to load on a computer), so I wasn't able to try adjusting them. Probably for the best, as there was also a little disclaimer at the bottom of the window explaining that it's not recommended for anyone other than Tesla technicians to adjust the headlights. (Since then I've also read the section in the manual reiterating this warning.) So I figured Tesla had simply disabled this feature. No biggie. I closed out of the window, exited the car, and went on with my day. 3 hours later I come back to find the headlights are on. At first I figured the car had failed to recognize that I had left the car and it had simply stayed on this whole time, but no... I checked and it was locked and off. Once inside I find that I can't turn off the headlights, nor can I turn off the ambient lights, and the dome lights won't turn off when they're in the "Auto" setting (but they will turn off in the "Off" setting). After trying multiple car resets, walking away from the car for 30 minutes, checking all the doors, plugging in / unplugging, etc., I call Tesla Customer Service. They spend 25 minutes having me try all the things I already tried, to no avail. Eventually they say they'll arrange to send someone out to fix it. This afternoon I got a call from a 'diagnostic technician' (I think that's what he called himself) asking me questions about the situation, and he suggested that there might be a bug in the firmware and he was trying to investigate the issue to pass information along to Tesla engineers. Then later I got a call from one of the mobile repair guys, and he says he can't get anyone out to me for a week, so maybe I'd prefer to take it into the Service Center instead. But if it's a firmware bug, I don't even know what they'd be able to do. Is there some kind of "hard" reset they can do at a Service Center that goes beyond holding the steering wheel buttons down? Normally I wouldn't care too much about a nuisance issue like this, but I was planning on going on a trip tomorrow and leaving my car in a public lot overnight, but now I don't want to since leaving the headlights on all night might attract unwanted attention. So I'm fairly annoyed (especially after how pathetically my first 2 weeks of "ownership" went).