Chosen Solution
I have a mid 2012 macbook pro. The uppercase stopped working on it, so I bought and replaced it myself, since it was out of warrenty. After putting it back together, everything worked, but the backlight just stopped working. I can see the screen with a flashlight, but it’s just really dark. The brightness slider is still coming up on the screen too. I did the pram reset, and smc reset, and all the other software checks, so it should be a hardware issue. Specs: Mid 2012 Mac book pro 2.3ghz 8gb 15"
The most likely cause it the logic board, which is the driver for the backlight. There is one particular part that tends to blow. So a new logic board would most likely be necessary. There is a slight chance that it is the display, but most likely not. If it is the logic board and you replace the display, your new display could be fried by the logic board. But I’m quite sure it is the logic board. A new one will run you about $400, and is a moderate repair for a non-technical person.
