Though the radio worked fine, the stock CD player in my '97 GTS didn't work when I got it. Here's what it would do: any time I turn the ignition on, the player tries to eject a disc, even if no disc is present. When I try to insert a disc, it will not suck the disc in, doesn't matter if the radio is on or off. If I push a disc in, it won't play, but still ejects ok. Any time it ejects, the ejector mechanism click multiple times. Here's a video showing exactly what it's doing:



The sensors that sense when you're putting a CD in are optical, and it seemed that they weren't sensing properly. Here's what I discovered when I took the head unit apart. I first took the CD player section out of the radio chassis(only 4 screws hold the CD player assembly into the radio chassis). The bottom of the CD player has three ribbon cable connecting the CD player to the main radio circuit board. When I pulled them out of their housings, I noticed that there were little dents in the contact surfaces. From the digital speedo in another car of mine, I know that this can cause all sorts of odd behavior. The way these contacts work is that there is a spring loaded "finger" that presses on the cable contact pad. Over time, the spring tension can dent the cable, making contact spotty. I wiggled these cables around a bit, and reassembled everything. Low and behold, it works! Here's a pic of the bottom of the CD player section. You can see dents in the cable. All three of the ribbon cables have similar little cable dents.



All you need to do is slide the cables out of the sockets far enough so the contact fingers are sitting on a new part of the ribbon. I did this fix back in July, and it's worked perfectly since.