Earpiece not working but everything else is?

Hello I really need some help.

I have no sound coming from the earpiece at all but both the front camera and proximity sensor are working perfectly fine.

What other thing could cause this problem is there any other things I could try.

I belive it is board troubles because i used the speaker and screen in another iphone 5 and it worked fine but what part on the pcb control the earpiece audio does anyone know?

All the resistor look intact but as I don't know what one to.look for im kinda stumped.

Any help would be grateful.

ThankThabks in advance !