I have a 3Gs running iOS 4.0, and the proximity sensor is broken. I have replaced the proximity sensor cable (cable #3 for those familiar with iPhone guts) but the proximity sensor still doesn't work. My best guess is that it's a motherboard issue (probably the clip for cable #3), which would be very difficult to fix (involving very precise soldering). The "workaround" I'd like to do in light of my broken proximity sensor is find an app that will let me manually disable the touchscreen during a phone call. As it stands now, iOS ends a call if you hit the "lock screen" button during a call if you are using the earpiece (if you are using speakerphone or headphone/mic then "lock screen" won't end the call). I want an app that will let me turn off the screen/disable the touchscreen during a phone call when I am using the earpiece to make a call. Anyone know of such a thing?