Dell Latitude 3540 15.6" - No Backlight ?

[AccountSaver]

Hello to all,

I have the Dell 3540 Latitude, that keeps really "dim" the display , even in BIOS.
To other laptops in the past that i have fixed, i have changed the "F" Fuse for the backlight  .
But on this particular laptop i can't find it anywhere.

Yes, i have changed the screen.
Yes, i have changed the cable.
Yes, i have tried different combinations but still nothing.

The display stays really dim . It doesn't have external GPU or etc. it's just dim.

Has anyone encoutered something like this, or can help me  out ? ( I can't even find schematics ) .

Thanks to anyone who will help.

[AccountSaver]

Noone knows anything ? At least any schematics ?