Screen is not going black during call
Screen of phone was replaced to aftermarket.
Everything is working fine except screen is not going black when you make call.
Replaced flex with sensors and its working right now.
The proximity sensor that's part of the front-facing camera and microphone flex is not positioned correctly in it's slot or the slot itself is not clear enough for it to detect your face.
You can test by placing your finger over the top of the phone screen across the microphone and front camera, it should turn off and back on as you over this area, you might find that you have to hold your hand directly on the glass to make it happen, this would tell you the sensor works but its not seated correct so its not sensitive enough to see your cheek while on a call.
Hi Haqaiiek, In addition to Keith's answer above, if it still doesn't work, you can also do a hard restart while phone is on, press and hold the home button and power button together for 10 seconds, let go of both buttons, the apple logo should appear and your phone will restart. If that doesn't help then you will need the sensor cable checked. I would bring it back to the place where you had the new screen put on. If you fixed it yourself, you can replace the Front Camera and Sensor Cable here for $29.95. There is also a Repair Guide that gives step by step instructions. The difficulty level is Moderate if you feel comfortable doing it yourself. I hope this helps. Please let us know, Thanks, John
Proximity sensor working well. Just during call screen is not going black.