I think my Navigation System is shot...We were recently on a 1500+ mile trip and about 1/3 of the way through the Nav started acting up. It wouldn't let me insert addresses or even cities correctly. We stopped at a gas station and started the truck and the screen came up, I hit agree, and all went gray saying it couldn't read the disc and to check and make sure it was the correct disc. I pulled the cover off the Nav player under the passenger seat when we got to our destination and it was super hot to the touch. Let it cool overnight and same message came up. I got a lense cleaner disc and tried that and still no good. Everything on the screen works as normal (a/c, radio, dvd, info, etc.) besides the Nav options. Any ideas would be helpful, we can live without Nav but it frustrates me that something in the Cruiser is broken...