Hi there. Yesterday my sat nav`s screen has gone black during normal driving and never went back to normal! The back light seems to be on I can still use radio etc. It has happened before but it fix itself after a few hours. What I noticed is that when I was driving across pot holes etc it was flickering but only for a few secs. I have tried to disconnect baterry, sat nav and leave it for a bit but it won`t work! Has anyone got any ideas what happened?