オリジナル投稿者： Brad ,
iPhone 4 definitely have proximity sensor issues. I have only been successful using frosted scotch tape colored over with a black sharpie pen. This is taped over the sensors (easy to do since it is tape) before the screen is installed. If you want to check if the flex cable is emitting the infra-red signal. Look through a video camera, the camera of another iPhone has worked for me in the past, while making a call, or using voice memos to activate the sensor and you will see it glow red-purple in color.