there are two power wires for a LCD screen. One is positive, one is negative. On the back of my DVD player, there is a 12V positive out that I should connect the LCD positive to. However, there is something worng with the voltage so the LCD powers up but no picture. What I did was hook my LCD positive to the battery, and the RCA cable going to the back of the LCD provides the ground. It works. The LCD powers on/off when I hit on/off on the DVD player. And the DVD player has positive, ground, and accessory just like a cd player but it will not turn on when you put in key, only with the key in and you turn it on with remote. Happy shopping and look at some Farenheit/Power Acoustik screens