I noticed the other day that my fans came on without the a/c needing to be turned on.
They may be set to only come on when it gets really hot. My temp guage was at like 3/4 the way to the top when they came on. Was climbing some pretty steep hills in the mountains of Western North Carolina. When I stopped and went inside a store, that is when it got so hot. Cooling fans cooled it right down though. Is your temp guage getting all the way to 3/4 and fans still not coming on?