I recently bought and installed a kenwood kvt-617. everything works on it except the dvd function and i cant figure out why. I grounded the parking brake wire with my ground for the deck. when i put in a dvd i dont even get an error message. all the screen tells me to do is eject. According to everything i see online i should at least be getting an error message if somethings not wired right..at least i think so? Can anyone help?