David Gearhart

I just purchased some gm factory headrest/DVD players (RSE - rear seat entertainment) and can't find installation instructions anywhere. A lot of it is self explanatory (fishing the wires down the seats) but it looks like the main control module made by invision has a special cable that should just plug into a jack somewhere (maybe underneath center console??). The main control module also has what looks like a headphone jack on it. Does anyone know if this is an additional a/v input or output. My specific part number is 23309584 but any similar part number would probably have similar instructions. It is going in a 2015 Sierra 2500hd. Any help is greatly appreciated. Thanks, David