Fans never come on unless the air conditioner is turned on. Seems to run very cool, temperature gauge goes up about a third of the way and stops, never any more. Car never smells hot, coolant level is always a-ok. I see only a thermostat switch which most likely has the duty to turn the fans on if the water gets too hot. Is that how it works. Is it reasonable that the fans never come on during regular operation without the air conditioning being turned on or might I have a bad thermostat switch...what's reasonable? Thanks,