OEM Radio wiring harness

I'm looking for some help from some of you that have experience with upgrading from the OEM radio. I've purchased the OEM Radio w/ DVD and rear seat flip down monitor and I've been told that the harness is already in place on all models whether the vehicle came with the rear entertainment package or not.

Does anyone have any experience with this? I would pull the radio and check right now but my truck is at the dealer. I'm trying to figure out if there are 2 or 4 connectors on the existing harness.

Attached are photos of both the radios, notice that one has 2 connections and the other has 4.

If this harness does not exist, does anyone know where I can get it? I'm also game for building the harness if anyone has a wiring diagram that they would be willing to share.

Thanks!

I haven't done it personally, but JP customs has a cable for upgrading to navigation, so I assume you'll need it.

Thanks Gambler

I appreciate the input and link. I may not have desribed this well enough. I'm not actually going to the Nav radio but just to the combo that has the DVD. If the budget allowed, I would definitly be upgrading to the nav radio, it looks really nice!

BTW, this is on my wifes '07 Yukon XL, not my '06 Tahoe in the picture.