i got a new dual in dash dvd player. I need help gettin it to play dvds while im driving. It has a parking brake ground also some kinda reverse wire that has to be tied into a light bulb or something. I had it working to play dvds by just grounding the parking break wire but everytime u turnt the unit off u have to re-ground the wire in order for it to work? If i hook a toggle switch up to it should that work or do i have to do something with that reverse wire? any input would be greatly appreciated.