My chevy lumina has only 39000 original miles. recently the temperature guage started fluctuating from one extreme to the other while driving. the driver's side fan comes on once in awhile and the passenger side not at all. when the drivers side fan comes on it only stays on a little while and does not affect the temp guage at all.

You don't say where you are.

You probably need a new thermostat. Cost for the part should be about $10. Labor to change it out should be $50 to $70, it takes less than an hour. Spring for fresh coolant, too.

The fans: the driver's side fan is activated by the A/C. I know, I know it's winter. But if you're running your defroster, you're running your a/c too. When the a/c is on, the fan can be on, too.

For the temp guage it sounds like the thermostat is playing up, you can remove the thermostat and either replace it with a new one or check to see if the original one is working by placing it in hot water and seeing if it opens or not, if it doesnt open then its nackerd. as for the blowers the first thing id check are the fuses, if theyre blown then change them, if not then leave them be, then id check the cabin filter or pollen filter whichever you know it by (wether this car has one or not i dont know) if it is blocked full of **** then replace it. thats all i can think of really, hope its some help.

I'm having the same exact problem. I've replaced the thermostat, all relay switches (there are 3 located under the hood in the 99 Lumina - 2 on passenger side, 1 on drivers side), replaced the Coolant temp. sensor....problem still exists.

When I run the A/C, both front fans will come on at low speeds (after about 30 seconds) and will stop & start intermittently for 3-5 minutes at a time. The highspeed fans never engage and the temp of the engine climbs rather high in stop/go traffic.
I'm looking for a wiring diagram as I suspect a corroded or cut wire at this point.