I have two different wiring harnesses to install the cd/dvd player with screen. One harness consists of only 4 wires that plugs into the car's harness and the other plugs into the infinity system jack. The infinity system harness has 4 rca plugs and one wire. I was wondering how to install it also how to install it where the dvd player plays while in drive vs being in park. I heard that i just have to ground the wire to something other than the parking