Chosen Solution
I DIY installed a new battery on my old 7+ but after I snapped the screen back in place, 3D touch won’t work on a certain spot on the center of the screen near the home button. I also found out that it works perfectly when the screen is loose from the body. And the certain spot stops working again after locking it back in the phone. i figured the battery might be pressing against the screen from the inside? what can i do?
Open your messages or any app with full white background and press the areas where 3D touch is not working and i you see that when you press screen changes color in that area is because something is pressing from inside the screen. If you see a weird color when you press probably you used to much double side tape, glue or you did not clean the old glue from the old battery.
