What would cause the drivers heated seat to suddenly not work when the passenger side does and all fuses are OK and the indicator switch says the seat is on?

I guess it could be the heating element in the seat. But i'd try tracing the wiring backwards from the seat if you can. Maybe something is just loose. Perhaps the indicator light is just stating that it's getting power at the switch and not at the actual heater. If you're electrically inclined, you might be able to find out some specs to check for resistance, and voltage at various points with a multimeter.