I have a 2002 Sunfire GTX, with a weird situation. Only the right front speaker works properly. The left front, you can barely hear, and the rears cannot be heard at all. This was confirmed palying with the balance and fade controls. I have the stock radio, and speakers. Any ideas what to look for, or how to trouble shoot further? I removed the radio, once before, and found no loose/cut wires, at the radio. Is there a fundamental issue with the stock radios, on the inside?