Brightness slider not working

[Foxdudes]

Hello I found a new issue with the brightness slider.
I can change the brightness easy with the night night/night/day buttons that works fine.
When I change the slider to lower or darker the board does nothing, it doesnt update, it seems like the slider doesn't give any output.

Is there a way to change a setting with a direct command in de raspberry console itself?
or how can I fix this problem?

Thanks in advance :)