Below are the two threads that I used to get started. If you can let me know the unit number on top of the stereo (you need to pull it to look), or the three letter code (like RBK, etc), then I can hopefully give you more accurate and detailed information. The website I used for my specific stereo model is no longer in service, so I am trying to find out if it moved already.
The Allpar site has excellent instruction for nearly all of the Chrysler stereos from a repair/restoration viewpoint.
Updatification
Allpar