This has now happened twice recently on longer trips: while driving on an evening when I had the interior auto temperature higher than normal due to the cold outside temperatures. The navigation screen went completely off. Interestingly, the rear seat entertainment system continued to play a DVD, however, no information showed up on the front navigation screen. No map, no satellite radio, no XM Radio. After switching fuses, which did not help, I was able to get the screen to come back on simply by pulling the fuse, reinserting. The screen would come on for approximately one minute before shutting off again. Then, after dejecting the navigation DVD and reinserting, same issue. Screen would come on for one minute and then go blank. Because the car felt fairly warm, I decided to put the driver's side temperature at 65 degrees and cool it down. Sure enough, the navigation screen after a couple minutes came back on and stayed on for the remainder of the two hour drive. I am thinking that the navigation unit under the screen has some sort of "heat trip". I also own a 2007 B9 wit the same config (RSE 7 Pas w Nav), drove for 60k in similar circumstances and had no issues like this. Was wondering if you might have had experience with that and if that's something that might be a faulty mechanism or if that is normal operation. Any remarks or helpful hints would be appreciated. Thanks!