Radiator light on
 

Hi, I have been getting a random radiator light for about three months on my five year old RX-8. The temp gauge shows all is well, it has plenty of fluid, and the fan does not come on for a long time after stopping. It comes on early and late, summer or winter (it's been in the 40s for the last month) goes out at random so it's not telling me anything, but it's REALLY annoying. Any ideas?