12 disc changer not being recognized

I have the stock 1997 am/fm/ with the 12 disc changer. Normally when I press aux on the radio it starts the CD changer. Any thoughts. I want to keep the car original as much as possible.

...sometimes my HU won't recognize my changer. When I go back to check on it and try to take the magazine out, I discover it's jammed and I never got an Err code. Have you ejected the magazine and reinstalled it to try the simple things first?