Chosen Solution
I obtained a water damaged Macbook Air whose display backlight wasn’t working. I replaced the logic board, and after that it worked fine, until today when the backlight went out again. Any diagnostic steps I can take to figure out what the actual problem is? I don’t want to replace the logic board again without knowing what the issue is.
If you have a multi-meter on hand you can measure the capacitors near the display connector in order to see if there’s backlight voltage present. if its missing (I Suspect it is) you can also check the fuse and check for a short across the capacitors to see if it might be a simple repair.
