I installed my cd player but it only plays the radio does play cd's

By "play" im assuming u mean no audio... check the wires, in the back there should be 2 blue wires, one has a white stripe... splice them together or reverse them... it sounds like you have it hooked up to the power antenna wire (should be solid blue wire) is sending power for the amp to turn on only when the fm is playing... you want the amp turn on wire (blue with a white stripe) to be hooked to that factory wires so when the radio is on your factory amp is triggered... if that doesn't work let me know there are other thing you can try...