Chosen Solution
Where is the backlight controller on the main board?
Heitor Scatolin if you picked the right device and your MBP is a Late 2013 that would mean your board is most likely a 820-3476. Your backlight driver is U7700.
This is a LP8548B1SQ-04 IC This answer is not to diagnose your logic board error but just to identify the component.
