half backlight , O/L diode mode reading on pin 35 of J4502

Hi , i have this iphone 7 with half backlight issue , i replaced U3701 but it did not fix the issue , I have an O/L diode mode reading on pin 35 of J4502 , FL3902 on this line tests ok , I have removed U3701 and lines from pads A1 and B1 seem shorted together .

I’m a bit stuck now ..

Hi , the phone originally had no or very glitchy touch and had no 5 volts on pin 11 of J4502 , the components on that line seemed ok so I replaced U3703 it still didn’t fix the touch , still no 5 volts on pin 11 .

After that I had the half back light issue , you were spot on with the diagnosis for that ,after scraping the underfill away FL3903 and FL3901 were indeed shorted , the backlight is good again now ..

I’m not sure how replacing U3703 caused that short as I didn’t heat that part of the board and they are heavily underfilled .