Do you see those wires sticking out all different colors look in there and tap your purple wire into that one. I am not sure about the wire you are talking about for the Yellow plug it could be a ground or a integrated power wire but I am not sure I would need a pic of 2. If you are talking about the 3 wires coming out of the camera. the yellow plug the black one and the red the black you ground the red gets ran up front to get power from the red wire I was telling you about and the yellow is the signal wire.