Dark screen after water damaage

Hi everyone,

Recently my iphone suffered light moister damage. Enough to set the triggers off, but not enough to corrode any connections (that I can see).

I have pulled the phone apart to try to clear out any moister but i couldn't find any there.

The problem is the LCD screen. The actual retina display works fine, but there is 0 light behind it, making it near impossible to see. I tried keeping the phone exactly the same, but used a different Logic Board within to see if it was just the screen or what, and everything worked perfectly.

So I have concluded there is something damaged on te mother board.

Does anyone know how or what to fix?

Is there any software reboots or tricks that might get it working?

(By the way, the rest of the phone works perfectly, i can receive calls, texts, take pictures, everything, its just the screen is really dark)

Many Thanks in advanced, your help is greatly appreciated