I have been having trouble with my radio in my 2002 Lexus RX300 SUV. I had a whole new stereo system put in about a year ago. Over the past few months, the stereo and CD player would come on and appear to be functional, but at times, the sound would just go out. Then yesterday, I got the battery changed, and now the radio/CD has no sound again. Is this a short, something electrical, or a faulty radio system? Any suggestions?