How can I make my car stereo think it has a CD changer attached? (Chrysler)?

[Matt]

My 2004 Chrysler Sebring has a spot in the back of the stereo to plug in a CD changer or a satellite radio... There is a "Mode" button that switches to this if you have it plugged in. I want to wire an auxiliary input into this spot, and I've read lots of material that shows it's possible, but I just need to get my stereo to switch to this input without actually having a CD changer or satellite radio hooked up. How can I trick my stereo into switching to this other input? It's a 10-pin plug on the back of the radio