Gauge Problems

[Mike_G]

I have two problems with my gauges. First of all the gas gauge only works when it feels like it. It will work perfectly for two or three days, but then it will just fall to the right and lay there. There doesn't seem to be any connection between when it decides to work and when it doesn't. Second, my gauges don't light up when I turn on the headlights. The headlights work and the dimmer switch and the gauges themselves work (with the exception of the finicky gas gauge). I haven't pulled the gauges yet, but what should I look for first as a cause and could the gas gauge and the lights be related?
-Mike