We went through the same garbage with our GS GPS. We had to return two of them before we got one that "works". In my OPINION, they are the biggest piece of garbage you can purchase. Even though the third unit would "work", it took us on crazy routes, turned off in the middle of busy traffic in a city, and was worse than not having one at all. I sold it to somebody who wanted it for 25 bucks three months after purchasing it. It was either that or toss it in the trash.
If you look at the Rand McNally GPS (7730) which is basically the same unit as the Good Sam version, you'll see that there are more 1 star ratings than there are 5 star! That says a lot.