So i work at a batteries unlimited store, of course I've been doing screens for months and never had an issue. I soon ran into a problem that had me stumped. I replace 5 to 6 screens a day and never have a problem. So the other day i did an iPhone 6 and have to switch everything from the old screen to the new screen and then ran into the problem of the proximity sensor not working. Usually we have a check list of things we check before we change anything to make sure everything works properly before and after, with the screen in the condition it was in i was unable to check the sensor to see if it was working. Switched everything over and not working so tried a new sensor and still having the same problem with it not working.....HELP!!! Mind you my customer drove miles for me to fix his phone so any answer or possible conclusion helps..