could be a temp sensor. may even be a stuck t stat. even with out fans in this cold weather if your moving, the car should stay cool.

in my truck i had electric fans on a switch, i used to turn them off in the winder and never use them unless i was plowing snow. im talking under 35 deg. no fans on. any warmer sitting still it would get hot.

and ive yet to hear my fans turn on this winter in my regal.