Aporte original por: Minho ,
The backlight on the 6 Plus is, in effect, a dual circuit. There is a drive circuit for the left side and one for the right side. In your specific case, it's hard to say if the problem is with the actual backlight (attached within the screen assembly) or if it is related to the drive circuit on the logic board. Ideally, you need to test the phone with a known-good replacement screen to see if the problem is consistent with the logic board or the screen. If it is a logic board issue, then this requires a micro-soldering repair and is not DIY.