How Do CD Changers Work?

[PewterBird]

My girlfriends new 96 bird came with a kenwood CD Changer when she bought it. The girl she bought it from said that the changer all of a sudden stopped working. I know how to install amps, HU's and speakers an all that, an I think I am pretty good at it, but never worked with a changer.
Here is what I know,
The actually changer has power, I can see lights go on inside it. There is one thick wire connected to it with like an oversized S-video type jack. In the front of the car, there is a controller, the controller will not come on.
It is connected by a smaller guage wire. Tommarow I will be removing the interior panels and hunting all the wires down.

Here is what I want to know:
What is a typical wiring setup?
If it is FM modulated, how do I find the frequency?
Can controllers be replaced?

[camaro_speedemon]

I have never worked with CD changers before. But, I would think you would be able to buy another controller for it. If not, you can buy HU that support CD changers.
If it's FM modulated, there should be some type of adjustment on it somewhere so you can change the frequency, not every place has a set frequency that is open. For example, 97.9 might not be used somewhere else, but its a radio station here. Just look for the knob and set it to a blank station and turn the knob until you here the CD changer.
For all the wires you need to hunt down, I think that one wire is all that the CD changer needs. I think its power, signal, and communications all rolled in into one.