iPhone screen dims randomly

I also believe that this is a heat related issue. It happens to me almost every day, but it always seems to be when the phone is connected to a charger, and specifically when the phone is warm to the touch.

This is not an Attention Aware issue. Yesterday my phone was dimming on its own yet again while outside and I was standing next to my partner who’s phone was not dimming. We have identical settings regarding Attention Aware and we both have any potential auto dimming turned off. My screen, even at its brightest, isn’t crisp and white like his. Additionally, the phone will freeze for no apparent reason so I took my iPhone X into the Apple Store and they ran a diagnostic test and found nothing wrong, yet there most definitely is something wrong. It was a huge waste of time and quite frustrating considering the price of this phone.

Hi, this is very simple. All you need to do is go to Settings->General->Accessibility->Display Accommodations and you will see Auto-Brightness. You can also just search up Auto-Brightness in settings.

My iPhone X dims on its own even when the auto dim settings are off. I brought the phone to the Apple store, they ran some diagnostic, it came up clear of issues and they even reset it. I still have the problem. On top of that, if I’m in iMessage and I type quickly the iMessage app will close and a random app will pop open. There’s no rhyme or reason.

For those who have not tried it yet

Settings > Face ID & Passcode > enter passcode > scroll down to Attention Aware Features and switch OFF

Panchososa694 I have to apoligize and eat crow... when you posted your original response regarding Attention Aware I confused it with something else. I went back through this thread and when I read your suggestion about checking Attention Aware settings I realized that I actually had NOT turned it off and neither had the genius’ at the Apple Store or was it suggested by the representatives I spoke to over the phone at Apple. As soon as I read what Attention Aware does, it totally made sense. Let’s see if this does the trick 🏼

I have been having this issue also. I have noticed it more while testing an app that is currently under development. It seems to happen when the phone has been under a considerable load. While debugging - I can see the energy usage of the app is very high. After some time the phone begins to heat up. While looking into this, I found another thread that said it was because of heat. I am tending to think this is probably right. After the phone cools off it seems to go back to normal.

I have the same issue. I have the X 2 weeks and has happened twice. All power save settings are off. I only have True Tone on. First time it happened a week ago, I rebooted and it was fixed. The second time full brightness came back after a minute so I didn’t have time to react, I only checked my settings and all where off. When it dims it’s like it’s on 70% brightness. This has previously happened several times on my iPhone 6 and was always fixed after a restart.

I agree 100% with you that it is a software issue. As stated earlier in this growing thread my wife’s phone, iPhone 6 dims all on its own too.

Hoping Apple finally sees this is a bigger issue as the engineers are fully aware of this problem and they even have video of my screen dimming.

Question for anyone out there, have you noticed the screen returning to normal if you let it be? An example, I was running Waze and the screen dimmed. I let it be, continued to run Waze and after 10 minutes the screen slowly returned to normal brightness. I could see it slowly return to full brightness. Just puzzles me that this is occurring and I bet it happens to the majority of phones but people either don’t care or realize what’s happening so they are not reporting anything.

If that happened to me and you're sure all brightness settings are correct, I would reset the iPhone as follows:

• Briefly press and release the volume up button.
• Briefly press and release the volume down button.
• Press and hold the side button until the Apple logo appears.

If that does not solve it, visit an Apple Store or Authorized Apple Service Center. Your iPhone is warrantied if this is caused by some manufacturing issue.

Same issue here. Mine only occurs if I am using it as GPS running Waze. It starts off nice and bright and after an undetermined amount of time the screen looks like it is about 1/4 of the way bright. When I check the brightness toggle it is all the way up.

If I turn the phone off then back on it resolves it. The phone does seem somewhat warm.

As others stated it’s likely a heat issue which stinks because my old iPhones never had the issue. Only noticed it after I got the X.

Check the attention aware features

https://support.apple.com/en-us/HT208245

Hey Anthony. I notice my screen dimming when my phone warms up a bit. My brightness will brighten back up when the phone cools down again. Perhaps it’s a safety thing the phone does to prevent overheating and exploding in our faces.

I just figured that iOS 11 has not only one but 2 Auto-Brightness settings options. My problem was more nonrelated with temperature (changing brightness while reading a book, just like with your wife) and after checking everything that it has been said on this thread (and on another one) I figured out that I had one turned on and the other one off. I have been using for a couple of hours now and it seams that the problem is solved.

Mountain-marimba wrote:

CVS drugstore has an app that displays a barcode on your phone

I use this app as well. My iPhone X has no brightness / dimming issues, but the clerk also has trouble scanning the barcode. I believe their scanner requires a very precise angle and somewhat precise distance for the barcode to be presented and recognized.

Now I’m not too sure it is a heat issue. I was driving today, using Waze and like clockwork the screen dimmed. I quit Waze and after a few minutes the screen was back to normal. I used Waze again and after like 2 minutes screen dims.

So I launched Apple Maps and no screen dimming. I had Apple Maps running for maybe 10 minutes all good. I switch to Waze and within 2 minutes screen dimmed.

At least for me it’s only when I run Waze. Now it could be iOS 11 feels Waze is making the phone hot and dims the screen to protect it?

Another thing I found was my wife who has an iPhone 6, her screen will do the same but she is using Safari to read books. She too is running iOS 11.2.6

So maybe it’s a bug in iOS thinking the phone is getting hot when in reality it isn’t?