Chosen Solution
I recently replaced the whole display of my iPhone 6S plus with the ifixit kit. I tested the touch functionality before sealing it up and everything seemed to be working fine. But as it turns out, the top 10% of my screen won’t respond to touch. So I can’t swipe down to get to notifications or use the Back Menu buttons in my applications. I’m pretty sure I’ve got all of the connectors for the digitizer seated properly but I could be wrong. The rest of the screen works well and it’s just that top 10% that doesn’t respond. Before opening it up again to check the connections, I wanted to see if there were any specific reasons why only the top of the screen wouldn’t be functioning. Hopefully that clue will give us a better idea where to start.
Usually it’s either a faulty screen or connectors on the board and screen need to be cleaned. You can use isopropyl alcohol and a brush to clean both connectors. Sometimes dust in the connector stops the screen from having a good connection.
