My iPhone 4 ps quit working recently. It is still under warranty but there is no nearby apple store to take it to and I'd rather see if there may be an easy fix before I ship it off and have no phone for a week. I can still see the faint red glow when I am on a call, but it won't turn the screen off...ever. It will auto adjust the brightness of screen when light changes just won't turn off screen in phone call. Any thoughts?