Confused about AUX button

I have a 1997 Lumina with a CD player/AM/FM stereo. I was hoping to buy an adapter for my new XM radio to hook into the back of the headunit and play without modulation. My radio does have an AUX button, so I think it should work.

HOWEVER... when I went online to shop for such an adapter... most of them say that they will not work on 95-97 models that have a CD player... only cassette.

Why would my radio have an AUX button if you couldn't hook up anything to it? Is anybody familiar with this situation?

Thanks..

I believe there is a wiring drop in the trunk for a trunk mount CD changer or whatever that is prewired from the factory. At least that's how my '00 Impala was,

I'd think if nothing else, you should be able to get an FM modulator so you just tune your XM through a dedicated FM freq.

Duh. I didn't read you don't want a modulator.

I think if you could find the wiring drop, and find the corresponding wires in the head unit's harness, you should be able to do it.

I have the CD head unit too, but the car originally came with the OE cassette unit. I'm looking at it right now, there is a block of 4 plug ins in a rectangle grouping, with a total of twenty pins, ten and ten, then there is a single plug in with 9 pins in line. They arent marked, so I don't know if the inline is the aux input.

Sorry

Well, apparently for pre-2000 models, the AUX button is for a cassette player, not a cd changer... and the AUX inputs folks make don't work for it.

Oh well.