I'm here...I think the thread split off into 2 topics. Stacks wants to reprogram the GMT-800 nav to non-lux and 07dmax wants to put the nav in his ride. Correct me if I'm wrong..
07 Dmax, IIRC, you should have the non-lux bose in your vehicle. I'm a little fuzzy, but you should have an amp somewhere. Do you have a bench seat or buckets?
The way the new body trucks work is that the nav units can have DVD capability or not. That's it. When you put a nav unit into a NBS truck, dealer programming is mandatory no matter what. They have to do a vin relearn if necessary as well as programming the radio to the truck itself through the TIS and Tech 2. You basically scan the truck, download it to TIS, check or uncheck items (backup cam, Y91 package,etc.), upload to the truck and it should work.
The only wires you have to add are for VSS(green/white stripe behind MBEC) and Onstar, which is optional.
I did this swap in my Denali and all the wiring was there but I still had to go to the dealer for programming. If you have a friendly tech that's willing to learn, it could be done.
The only thing that strikes me is the fact that all you see is a white screen. Does it do anything else?