I have an '06 Commander Limited which I just bought. I've been having trouble with the Nav screen just randomly not coming on when I start the car and randomly going blank when i'm driving down the road. It will also randomly come back on. I'm not sure if there's some secret button to push to get it to come back on, or it needs an update, or it has a short..There's no pattern as to when it goes out..Anyone else ever had this problem?? HELP!