I have a 2005 Pontiac Sunfire. The instrument panel cluster does not light up, nor does the radio buttons, fog lights, tail lights, gear shift light or the a/c, heater light. We've changed several fuses for the above and this has not fixed any of the problems. What else could it be?

Thanks

You probably have an open circuit in the Dimmer or dimmer circuit:

Attachment 11515

Verify the ground is intact and check for power on the Gray wire when the lights are on.
If that doesn't check out as good, it's possible that the Body Control Module (BCM) has failed for that system.

Hands-on diagnosis is crucial to pinpoint the fault in any electrical system.