98 eclipse radio seems to work but the speakers do not

I have a '98 Eclipse, with stock everything. So I know this isn't caused by something I've replaced.

The deal here is that the stereo powers on, allows me to tune to stations, plays CDs and cassettes, but I get no sound (not even a hiss) from any of the speakers.

Ironically, I tried to plug in my TomTom yesterday and I also got no power from the 12v lighter to charge it. I don't know if this could be connected with the stereo problem?

Everything else--lights, A/C, the motor for the convertible top, etc.--is working fine. I can live with having to charge the TomTom on my laptop, but not having music to listen to on long drives is really driving me crazy!