Hel pon 2008 Suburban

2008 Suburban. Looking to add a GM accessory overhead DVD player with the docking station. I want it to play through the speakers not just the headphones. The guy at GM said it will only work with the headphones. Who makes something that will let me run it through my factory speakers?

whats in the dock? If its got a head phone jack or rca outs, then you could do fm modulation. If you really want to get fancy, you can do an auxliary connection IF you have a CD changer button on your radio and you dont have cd changer