Help me please!

Sure it wasn't on before you updated to Win 11?  Dell says this PC model is compatible with Win 11.

Does that LED go off when PC is shut down normally from inside Windows?  Does it blink or change color when you power the PC on, before it gets to the Windows desktop? If it blinks, count the blinks which is an error code. Blinks come in two groups, eg 2 blinks (brief pause), 1 blink (longer pause and repeat 2, pause,1).

Nothing is marked in the picture of the front panel on this PC model, but it might be the Power status light. In that case, a solid amber means: "System fault during pre-POST, but power supply is good (S0) "

Open Device Manager and click View>Show hidden. Then look everywhere for any device(s) marked as having a problem and/or any "Unknown" device.  Let us know what you find, if anything...

It goes out - when I turn off the computer.
In general, he behaves like a normal WHITE. It does not blink - it is always ON when the computer is turned on.
However, I did not notice any problems with the computer. He updates windows. Itself - does not turn off and is not overloaded. That is, it works stably. All tests that are in the BIOS pass successfully.
I have another one (from my wife) - I took a power supply from it for the experiment - nothing has changed.
I also tried to change the RAM, m2 disk, hdd disk - all this also did not work!
What else to do - I do not know ...

Device Manager - all ok

You could try clearing BIOS by removing the motherboard battery:

1. Reboot and start tapping F2 when you see the Dell splash screen to open BIOS setup
2. Copy down all current BIOS settings, to be safe
3. Power off, unplug power cord from rear of PC
4. Press/hold power button for ~15 sec
5. Open case and remove motherboard battery (check Service Manual for details)
6. Press/hold power button for ~30 sec
7. Reinstall battery (Good time to install a fresh CR2032 3-volt coin cell battery)
8. Close up
9. Reboot

CAVEAT: I don't know if clearing BIOS will solve this problem...

Many THX RoHe!

I made absolutely all the points.
Unfortunately, the miracle did not happen.
Now I do WIPE on all disks. Return to factory settings.
Maybe I'll try downgrading the BIOS.
At some point, I thought - perhaps the INDICATOR has broken and it only lights up in orange. But then I took out the battery (2032) and turned it on without it. It started flashing white and orange. And I realized - that the indicator is NOT BROKEN!!!
I don't know what else to do.
Computer is working. All tests pass properly (both in BIOS and online on the Dell website)
Support - does not want to help remotely. They say visit the office. But now there is a war in my country... I don't know what else to do...

Wiping your disks and returning to factory settings isn't going to fix this.

What version of BIOS is running?

Did you compare the BIOS settings you wrote down to the settings after you removed/reinstalled the battery? Are they all the same?  Did you install a fresh battery?

Did you check in BIOS setup to make sure the date/time are set correctly, especially after you cleared BIOS?

To downgrade BIOS, you will have to enable the BIOS Downgrade option in BIOS setup first. Downgrading BIOS can be risky so this is entirely your decision and you accept the risks.

It might be safer to try a BIOS Recovery. You'll need the BIOS Recovery Image File .rcv file for whichever version of BIOS is running now and an empty USB stick.  There will be a link to .rcv file on the same page as the BIOS update .exe file for whatever version of BIOS is running now. No way to know if a recovery or downgrade will solve this issue.

As long as PC is working normally, you may want to leave it alone and ignore the amber LED. 

Stay safe!

You don't want to downgrade BIOS too far because you'll be removing all the fixes and updates added to more recent versions. And you don't want to break this PC, especially since it's working now.

I'll see if any of my Dell contacts have any suggestions...

One more thing...have you disconnected all USB devices that are connected to this PC and rebooted?

Yes. I used three different 2032 batteries.
Duracel and others. Got it from my wifes computer.
Of course, this did not solve the problem.

I flashed the bios to the same latest version as it was.

Version

1.16.0, 1.16.0

Tomorrow Ill try to downgrade 1 or 2-3 versions below.

Wipe disks did not help either.

In principle, I agree that it is possible to live with this orange light further. But I want to beat him!

'Cause I know its not right. And I want to fix it!

And I cant understand the position of OFFICIAL DELL support.
Its a very terrible experience. I have 6 devices from Dell.
3 monoblocks and 3 laptops (Mine, wife and son)

Some of them are not out of support yet. And now I know for sure that their support is money down the drain. I have never met a more brutal attitude!

And a big thank you to you Ron - you are the only one trying to help me!!!

Hi again Ron!

1. Yes - I disconnected all devices and rebooted.
The result is consistently zero!

2. Downgrade didnt help either. Downgraded to three versions. Until the very first version!

There are three of my monoblocks in the photo. And a problematic monoblock with an extended 2032 battery (without a battery, it blinks three times white and once orange). I took a photo to show that he can shine just white )))))

3 amber, 1 white is the correct blink code for a CMOS battery failure, which you'd expect when the battery is removed. 

Is this PC connected to a power strip, surge protector and/or uninterruptable  power supply? You might try removing all of those and see what happens when connecting PC directly to the mains.

Just keep using it. You'll make yourself crazy trying to figure this out, as long as it's working OK.

I pinged my Dell contacts to see if anyone has any info that might help. 

Thats right - at the moment it is connected to the UPS (we are out of town). But the problem started a week ago (at that time it was connected directly to the network).
As well as now 3 Dell monoblocks are connected to this UPS. Of these, two glow white. (of these two, absolutely the same model / configuration. OS, etc.)
As for going crazy. Im close to it
I basically tried all the options.
The last thing left is to disassemble it completely (all the connectors) and reassemble it. Maybe a connector got dusty.
But how it coincided with the Windows update is a mystery to me.
+ I dont understand - why all the tests pass EXCELLENT - and at the same time the indicator color error. Why are there no errors in the BIOS logs. How is this possible????

Have you tried swapping the power adapter from an Inspiron 5400 AIO with white LED for the adapter used on the one with amber LED?

If it turns white with the other adapter, test the "amber adapter" on the other AIO. If that other one now stays amber, you have an adapter problem and it probably needs to be replaced.

This was done in the first place.
I checked THREE!!! 90W adapter Dell!
Nothing has changed!
Ron - thank you for being with me!

Are the 3 adapters all designed for the 5400 AIO? Some/many times you can't mix adapters with different PC models...

Running out of ideas. I'll see if my Dell contacts have had a chance to think about this...