iPhone 17 Pro's Auto-Brightness sensor not detecting complete darkness

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iPhone 17 Pro's Auto-Brightness sensor not detecting complete darkness

iPhone 17 Pro Auto-Brightness Sensor Issue

Until very recently, my iPhone 17 Pro screen would go completely dark when the room was dark. This was great for sleeping. And yes, this was with Always On display active. Now it seems the sensor doesn't register that the room is completely dark, and the screen remains fairly bright. I have troubleshooted with hard restart, and I've ensured the Auto-Brightness feature is toggled on. Anyone else finding this issue?

(I'm on the latest iOS 26.1)

[Re-Titled by Moderator]

Original Title: iPhone 17

Posted on Dec 1, 2025 9:16 AM

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Answer 1

Top-ranking reply

Ingo2711

Community+ 2026

Level 10

80,895 points

Dec 2, 2025 8:50 AM in response to Kirk2Enterprise

Before you contact the official Apple Support to get your iPhone diagnosed or visit an Authorised Apple Service Provider and show them the issue, you should try to set it back to factory settings, to rule out a software issue.

To rule out defective data from the backup, set it up as a new device and test ambient light sensor.

Restore your iPhone, iPad, or iPod to factory settings using a computer - Apple Support

If the sensor works after that, restore from the latest backup and test again.

In case the sensor still does not work correctly after setting it up as a new device, this is a hardware issue and the iPhone has to be serviced:

Apple - Support - iPhone Repair and Service

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Answer 2

Dec 2, 2025 12:43 AM in response to Kirk2Enterprise

Any screen protection or case attached to the iPhone?

Does it work, if Always On Display is off?

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Answer 3

Dec 2, 2025 8:28 AM in response to Ingo2711

Hey thanks for responding! Yes it has a screen protector that Apple put on, and it was working fine with it until about a week ago. The screen will go dark if Always On Display is off. But it was going dark before, even with AOD on as it would respond to the dark bedroom.

It seems now that the screen only goes dark when I place my finger over the sensor, covering it completely. But sitting in a pitch dark room, it stays illuminated.

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iPhone 17 Pro's Auto-Brightness sensor not detecting complete darkness

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