Hi HONEBOY,
I think this might be to do with how the unit is fitted. There's a light green wire at the back of the unit that's supposed to be connected to your handbrake/parking brake. I believe it has a button on it that enables/disables the video functionality of your stereo when the parking brake is applied or not (the idea being that when the brake is off, and the car might then be moving it is not possible to watch a video for safety reasons).
I think the first thing to check is how this light green wire has been installed as I would say this is the most likely cause of the problem.
Cheers
