Is there one plug which handles all speaker outputs. Could be loose connector.. You could also have a bad ground for audio output if no sound anywhere. How many speakers (6?) If you can access the output connector, grab an ohmmeter and check each speaker lead. Should be between 4-8 ohms. If below 4 ohms or zero resistance, you've got a short and possible damage to audio output stage. I don't believe the preamp sections are separately fused as these are low power devices. Outputs may be fused. If all the head end stuff is working and you sit in silence, it's probably a connector or a shorted, damaged output stage. if you aren't up to troubleshooting this kind of problem and the warranty is no help, find a local who does car stereo work, and he may get you headed in the right direction. With no sound at all from any speaker, it really sounds like a connector. Hey, good luck...