It's supposed to always be on because otherwise, you can't press any of the buttons. But it's also supposed to dim if you move the laptop to a darker room.

Hey @Nomadsland​ , I think that's the problem, it is on really bright all the time ... as if the light sensor is broken :(

I have noted this too as the backlight is really high whilst during the restart it does show less brightness. Can someone from Dell investigate and provide a solution?

Function key backlight remains super bright. Also, keyboard backlight continues to function even after selecting "disabled" in the bios. Computer has latest updates and has passed all hardware tests. Very annoying but computer is now out of warranty