when I switch to CD player it's wont play CD's

Sorry. In that era, GM had a 100 percent failure rate on their cd mechanisms. To lock up all the repairs for themselves, they stopped selling radio service manuals and parts with the '94 model year. There ARE some places you can find on the internet that will replace the cd mechanism but if you ever though of buying a high-quality aftermarket radio, now's the time. You can also go through the dealer to get yours repaired but the cost will be around $350.00.