iPhone 12 screen brightness issue

Yes it’s heat. When sunlight hits even inside an AC cabin the rear of the phone can get really hot by sunlight Alone. I have tested this extensively with a IR temperature gun.

Trust me when I say the iPhone 12 is very much intolerant of heat and will dim the screen as soon as it gets hot. Much much quicker than any previous iPhone.

Mine never bounced back. I chatted with support and they suggested a factory reset. That seemed to work (I am only a couple of hours in). Crossing my fingers this will resolve the problem.

Please read what I wrote earlier. It’s iPhone safety function to keep the phone from overheating. There is nothing you can do about it until the phone cools down. Stay out of the sun.

I'm familiar with the iPhones turning dim while overheating, but it's pretty clear when this happens. For me, whenever I was outside in ~90 degree F while doing something intensive on the phone with full brightness, AKA in music with GPS, intensive app game, steaming. I understood the screen went dim because the phone was warm and I was using it more than normal in hot temperatures.

Now with my 12 Pro, after just plugging the phone indoors to charge and starting up a game, the phone instantly went dim as if it were overheating which is strange because the phone wasn't warm; the sun wasn't out nor was I outside to begin with. Brightness slider at max was still really dim, bringing it down makes the screen barely visible. After pressing the sleep button once and waking the phone, the screen was at normal brightness like normal. Maybe the phone is really overheating in just that one moment in some weird programming logic way, or it simply a bug/hardware issue. Maybe I'm unlucky and the other replies are overheating issues, I'm not sure. But it's definitely happened more on the 12 Pro for me compared to my old 5s, 6s, and Xs, not once did those phones get dim unless the phone or the environment were obviously warm. At least, I think it should be looked into.. this thread has a good number of replies compared to what I've read of older phones tbh.

Contacted apple today. Support confirmed to me that this is “working as intended” and that the iPhone 12 dims screen if too hot to protect itself.

This happening with 79F sunny weather is ridiculous.

the issue is with heat. The phone heats up rather quickly unfortunately, and then activates it’s protection modes including dimming the screen.

There is a technical article on apple website explaining this. It’s not conjecture.

It's very simple. It has nothing to do with auto brightness / accessibility settings etc. I've had almost all models of iphone and not had this problem except in cases of extreme heat on the dashboard while navigating and then the phone has told me it is overheating and shut down. And it has nothing to do with the type of case you are using on your phone - surely Apple know that everyone will use a case and most of these will almost completely enclose the phone. No, it is an overheating / hardware issue - it is random, unpredictable and very frustrating. Apple continue to be in denial about it (2 visits to store so far) as they have so many billions tied up with it and a recall would cost them a fortune. I am now waiting for a replacement and, if it happens again, as I suspect it will as it has for so many others, I will send it back for a refund and go back to my very reliable and much-loved Iphone 7 plus until they sort out this mess.

It happened to me too. Just tell Siri to bring screen to the brightest level. You do not have to wait.

I do not know if we have lemons or not but there is a huge difference in brightness between my 12 pro max and an old 7 that I am using for work.

12 pro max always acting strange when out in the sun. I gets dark like instanly. Then gradually , in the shade is getting brighter and brighter. Very strange. Only reason I can see is the temperature. The hottest it is the darker it gets.

Same here. Apparently is happening because of the high temperature of the phone. I literally seen the screen lighting up gradually inside the car in front of the ac after this “darkening screen in the sun” happened to me.I didn’t find yet a solution but I trust someone will. Until then keep your phones away from heating

This is because of the use of completely different display technologies: OLED vs.LCD.

Most of Apple's current offerings, like most premium Android phones, use OLED technology where colors are more vibrant, contrast is higher, and dark areas darker but at the cost of some heat generation as each individual pixel is lit by itself; if it is black it is off, if it is to be on, it's on at various brightness levels as needed to form colors on-screen.

If you want a phone where the display will stay on at full brightness all the time, look for a phone with a backlit LCD display where LEDs light the area behind the LCD display and you see the areas of light the LCD lets through.

Of the current iPhones, only the iPhone SE has an LCD display.

Another alternative if you need a backlit LCD screen would be to use a cellular-enabled iPad as your mobile device.

Note that most premium Android phones like the Samsung Galaxy S21 Ultra and Google Pixel 6 have also moved to an OLED display for the same reasons Apple did; to get an LCD display you have to move to a smaller or lower-end model or a tablet just as you need to with Apple's devices.

Complaining you can't have the phone at full brightness for long periods of time is like complaining you can't drive your car with the gas pedal floored all the time.

Most importantly, if using your phone becomes a hazard to driving, turn it off and put it away until you reach your destination.

(I'm frankly still amazed Uber and Lyft haven't yet been sued for their drivers being distracted by having to have their apps on. Also food delivery services.)

I can confirm this is due to a heat issue. Your screen will limit max brightness in order to help cool your device.

Have you tried going to apple store for replacement? Of course there's always the chance they'll say nothing is wrong unless they physically see the phone dimming

There is to date no known fix. It’s as designed according to Apple themselves. That’s what they told me on the phone. I believe it. I don’t ever expect a fix.

If it was over 95ºF and/or in direct sunlight, I'm not surprised, it's expected.

I think if the phone is charging and gets too hot it will dim automatically when it cools down it will go back to bright again. Safety feature