Interior lighting problems....

I am having trouble with the interior lights coming on, well there not coming on when i turn the lights on. The headlights, taillights etc work. However the dash doesn't illuminate, nor does the a/c control swithes or cc & auto 4x4 switch. I don't have the cover for the fuse panel on the inside kickpanel, but I did check all of those fuses & all are fine. Could it be a problem with a relay? Is this a common problem? Any info would be great.

Does the dimmer knob on the dash have any effect? The dimmer could be bad.

G/luck
Joel