My radio does not work!

The radio in my car works very poorly. The display no longer functions and the radio only works when I am very close to the station. I have the preset stations memorized before the display stopped working. However, the CD and cassette parts still work fine. I am trying to figure out how to fix this. I have taken the dash apart to confirm that the wires are securely attached in the back and the wires underneath the glove box are securely attached as well. I am not sure if this is a problem with the wiring within the car, the radio itself, and or the antenna. If I need to replace any of the wiring, what type of wire should I use? If I need to replace the radio, which Jeep models are interchangeable with mine?