First and foremost, when working on a cooling system, you want to check and see if the system is under pressure to prevent being burned from hot coolant when opening the system. You should inspect the cooloing system for being low on engine coolant by viewing the level in the radiator. If the level is low, on the front of this engine above the water pump, you will see the bleed valve for the cooling system. The small center bolt head is most likely 8mm., you open that bolt by turning it counter clockwise. After you have loosened this bolt on the blled valve, you will then start filling the radiator with engine coolant, while viewing the bleed valve. You want to continue filling the radiator until there are no air bubbles visible and a steady stream emits from the valve and then re-tighten the bolt on top of the valve. You can also remove a coolant hose, and achieve the same results as the valve. I am mentioning this because sometimes the bolt on the bleed valve is broken off flush, or breaks off trying to loosen it. You always want to find a coolant hose that is the highest point of the cooling system. Same thing as the valve, you want to see a steady steam of coolant, with no air bubbles visible, then re-attach the hose you removed. Note: this peticular engine has TSB's for engine coolant loss, due to inferior intake gasket's and or head gasket's.
As for the question for the fans, it is possible that the cooloing fan switch/sensor is defective, or due to low a low engine coolant condition, indicating a false reading to the actual cooling fan switch itself. There is a relay in this system for the cooling fan, and there may be a concern with the relay or battery power feeding the circuit. These things must be inspected for proper diagnosis.