Оригинальный сообщение: Josh ,
Try reseating the Display data cable and the ambient light sensor. Those are the only cables that could affect the brightness settings. If that doesn't work, your last resort is a restore. I'm doubtful that it would be a software issue, it's more probable that a part was damaged (static?) during the back casing replacement. Let me know if that works. If not, we'll move onto the next steps.