Chosen Solution
My 2012 13” MacBook Pro’s display doesn’t show an image and the backlight doesn’t light either. Connecting system remotely via TeamViewer app (screen share app) from another computer shows the display is detected within the system. The system has no water damage and history of the device is unknown. pictures of logic board screen connecter
Using a flashlight shining in through the Apple logo in the lid are you able to see the image of your desktop and its icons? If you can then the issue is strictly within the backlight logic. If not you may have some liquid damage on the logic board where the display cable is connected. Let us know if you see the desktop & icons. In either case follow this IFIXIT guide: MacBook Pro 13" Retina Display Late 2013 Display Assembly Replacement Do the first six steps, then jump down to Step 11. After you’ve disconnected the cable take some pictures of both ends of the cable as well as the logic board connector and paste them here for us to see Adding images to an existing question
