My saab 9-5 radio will not turn on. I checked all fuses including one on back of radio. It seems to be getting power because if i plug it in while the car is running i can hear the cassette motors. It started when i put a cassette back into my car to listen to my iPod, it was then stuck in tape mode and none of the buttons worked but the steering wheel controls worked and i could play music through the cassette tape. Then one day later nothing worked no lights, no power, nothing. What is wrongggg!!!