If you don’t find the auto-brightness feature really that useful, you can simply turn it off. Unfortunately, your iPhone display may keep dimming while you’re using it even after disabling auto-brightness. For example, your display can go from bright to dark and then back up without any apparent reason.
How to Prevent Your iPhone From Dimming Screen Brightness
Disable Auto-Brightness and True Tone
Try disabling both Auto-Brightness and True Tone and check if you notice any improvements. True Tone may override your current brightness settings in order to adapt your iPhone’s display color and brightness to the light in your environment.
Navigate to Settings, select Display & Brightness, tap True Tone, and toggle off this option. Then, go back to Settings, select Accessibility, go to Display & Text Size and disable Auto-Brightness.
If the issue persists, try turning off Low Power Mode and check the results. You may want to disable Night Shift as well.
Check if Your iPhone Is Heating Up
If your iPhone heats up, don’t be surprised if the screen auto dims despite having auto-brightness turned off. The screen will automatically dim after reaching a certain temperature threshold. This is intended behavior to prevent hardware damage. Your iPhone may overheat simply by being in your pocket, due to prolonged sun exposure, when watching video content while the device is charging, and so on.
Force-stop all the background apps, remove the case, wait until your iPhone cools down, and check if the issue persists. To speed up the process, you can turn off your iPhone completely. If your device remains idle for a while, display brightness should no longer fluctuate on its own.
For more information on what to do if your iPhone gets too warm, go to Apple’s support page.
Get the Latest Updates
Unexpected software glitches could be the reason why your iPhone screen brightness jumps back and forth from bright to dark. If you’re lucky, the latest iOS updates may pack a hotfix for the issue you’re experiencing.
Go to Settings, tap General, select Software Update, and check if a new software version is available for your iPhone.
If your iPhone screen dims on its own even with auto-brightness turned off, disable True Tone, Low Power Mode, and Night Shift. Additionally, check for updates and install the latest iOS version on your device. If your iPhone heats up, the screen will automatically dim to prevent hardware damage. Remove the case, close background apps, turn off the device, and let it cool down.
Did these solutions work for you? Let us know in the comments below.