I picked up a seat in dash cd changer off of Ebay this week. Came this am, so quickly took it out the box and plugged in the blue connector along with original green (with earth lead) and yellow. Swiched on ignition and got nothing! There is another black 2 pin connector on the other side of the changer, is this just for illumination or is this power for unit. Have i bought something else off Ebay i can't use cos i'm a twonk!!