I was wondering if someone could help me. I've done a forum search and so far only come up with issues with the proximity sensor. The iPhone 4 I have is a black box replacement from an Apple store. It does have the pesky problem with the proximity sensor, but I have an additional issue with the ambient light sensor. For some reason the phone has a hard time telling if the room I'm in is dark or brightly lit. The brightness goes down whenever the room goes dark. If I point it to a light source (e.g. my laptop screen) the brightness goes up again. I'm sure this is supposed to be the other way round, right? the questions I'm asking are, does anyone know if this is part of the same issue with the proximity sensor? Has anyone else noticed this? I've made another appointment at the "Genius" bar (term used very loosely ) but thought I'd ask on here as well. Any help much appreciated.