[kqh101]

For adding a cd player to the head unit from a car that didn't come with the optional slave cd player, you would have to change the wiring harness in your car. I don't have the part number with me now but it has the extra power cord that plugs into the cd player and also the audio transfer wiring (gray plug with a black wire ground) that plugs between the cassette head unit and the cd player player. Note that this wire fits in the top right corner (square plug). There is a jumper plug presently there that you would have to remove from the cassette head unit.