Compass/Thermometer works...not..sometimes

It usualy works for the first 10-20 min but then shuts off, sometimes it will come back on after pressing the temp button but most of the times it won't.
http://tinypic.com/4qhn4z

I've had my '99 a little over a year now. My compass always works and works well. But the thermometer only works sometimes and is dead on and other times is wildly off. Like when it's actually 70 degrees out it might say -30 and "ice".