speaker and proximity not working

Hi everybody, just wanted to share this problem I had with a customer iphone 6. the earpiece speaker and proximity sensor are not working when I try to make a call the speaker button on the phone is grayed out also. I tried new proximity sensor and a new speaker still the same problem. After hours of testing and replacing parts the problem was not solved. I wanted to see if there is anyone out there that came across the same problem or even knows what it could be from. Thanks in advance.