2004 GMC Savana Conversion Van Replacement DVD

Trying to help out my dad that has a 2004 gmc savana conversion van by replacing the dvd player with a newer one and was looking at the wiring. Has a green cord, an orange cord, and a black ground. I figured out that the green is power, and the black is ground, but still confused on the orange wire. The new units only have a power and a ground on the factory harness that comes with it. Any ideas? Can't find a factory replacement, so have to go aftermarket.