Chosen Solution
I just replaced the battery with a fresh one and now the entire front assembly accept the screen and home button won’t work. I’ve done a few hard resets and reconnected the cables and it still won’t work.
These cables are super easy to irritate with minor twisting. Try turning off your phone, disconnecting your battery, disconnecting and reconnecting the sensor (after ensuring the male/female ports are clean) and then reconnecting the battery and powering on. If the issue persist I’d suggest purchasing a new proximity sensor to check against a small tear or damage that isn’t obvious to the human eye. iPhone 6 Front Camera and Sensor Cable
