I have the same problem. I have a 6 disk CD changer in the trunk and it was acting up, and a few days ago stopped working altogether. I pulled the DC changer out and put a volt-meter to the cable. With the stereo off, there is power at one of the pins, which I assume provdes power to the unit to eject the CD magazine. With the stereo on, there is power at several more pins. So, I'm assuming the fault is in the unit itsself. I thought, I smelled some elecrical burning just before the unit quit on me.
If you need to get your CDs out, there is a switch which allows you to manually eject the magazine. On mine, a piece of tape over the switch showed you which way to move the switch. You'll need a small screwsriver or other pointy object
VaBeacher, November 2007