The fan should come on when the temperature is on the M in normal for a while, it does on both of our V6 Mystiques. The temp should drop and the fan will stop. That is "low speed mode" same as when you turn on the a/c and the radiator fan starts. I have found the (noisy) high speed mode comes on (low, high a minute,low,hi etc) if the a/c is in use on a very hot day 90 degrees. I have had a "moan" come from the air filter box if I restart the car after stopping in a store for 10 minutes, hot day. You will feel the vibration in the plastic box, and then it will stop by itself. Something to do with emissions control, I think.
I studied the fan system, after replacing my waterpump, and watching for any sign of overheating.
