F30 2012 black screen

Hello all,

Not sure if appropriate but I feel desperate.

My screen suddenly went complete black, no logo no light of any sort. No audio no Bluetooth not even when seat belt is off. I have checked front and boot fuse, it seems alright. I have stripped the front, checked all the wiring seems ok.
I have changed the head unit to another one and still nothing works. When checking for errors om bimmerlink, head unit not showing. I have also took the battery off for like 30 minutes so the car resets and still didn’t work..

I am desperate to find a solution, been looking everywhere, i would like to try and fix it my self as paying at a garage is pretty expensive and I would use this option as a last resort.

If anyone encountered this or would have any clue and can help, I would be forever grateful! Thank you!