Hi jj1355810, the led logo you tried to add works making contact with the pins the backlight uses to connect to the lcd and takes power from that. It looks like you damaged that part or the backlight itself making contact between the different pins of the backlight shorting them. I would suggest to try to resold the pins of the backlight or try to put a new one, it's not a difficult operation but the 6s' backlight is way more expensive because it contains the touch 3d chip. Hope this can help you.