Chosen Solution
Replacing the cables after putting in the new battery, there is this warning at step 20: When reconnecting the digitizer cable, do not press the center of the connector. Press one end of the connector, then press the opposite end. Pressing in the center of the connector can bend the component and cause digitizer damage. What does this damage look like? I hooked everything back together for a test and the phone functions BUT: there is a black patch about where the wi-fi, battery charge is shown, and wide grayish vertical streaks on the screen; the screen is also slightly faded. Did I damage that connector? The screen was fine before.
The connector on the 6s isn’t too bad its mainly the plus that is temperamental because the connector is physically longer… The problem u describe sounds more like a faulty screen. Disconnect and check the connectors though make sure it’s not bent and the pins dont look like theyve come away from the flex
Well what happens sometimes is that the connector becomes a bit concaved. To fix that you put one finger above and one under and attempt to flatten the connector back very carefully. If you look at the pins carefully on its side you’ll see where the bend is very easily if there is one.
