When I try to use the turn-by-turn navigation in "Maps" there is no sound. I've turned the volume up all the way, but can never get any sound to hear the turn-by-turn directions. I just doesn't work. My husband's phone works perfectly and we don't see any differences between the two. I've rebooted and it didn't help. I'd really like to use the navigation, but it's useless if I have to keep looking at my phone to see the directions.