Front Camera Replacement Gone Wrong?

Hello to everyone i need an expert advice on this: I got a broken device from a fellow, clean from icloud and i bought it to repair it, and gift to my mom. Replaced screen , Rear Camera, Rear Glass (with OR Coil) no problems. Front camera was working but was a mess of an image. Face ID works fine. When i tried to replace the Front Camera with an new individual camera , the phone didnt recognise it. Switched back to original Camera , the phone didnt recognise it also! Face ID still works! Key Point is i had to carefully remove the original camera from the Assembly. But i cant get it to work... Any ideas? I have tried software update, reinstall from DFU, put the original rear camera back, check the connector under microscope. I keep thinking its something electrical, something doesnt make contact to ground etc. PS i would like to keep the FaceID function as its really handy for my mom. Thanks