Eclipse does not have a device to allow tapping in to the CD changer inputs. I had this same issue when I put the stereo system in my wife's truck. In it we have a Eclipse 55060 head unit in it. If you want full details on that system check out her trucks profile on our web site. (www.autotoyz.org) To get around this we had our installers put in a 22010 EQ unit with the head unit, and the MP3 player. It has a built in A/B switch and gives you the ability to tailor the sound configuration to your taste.