A radiator fan control module is a component of your vehicle’s engine cooling system. The radiator fan assembly, also known as a cooling fan assembly, is mounted directly behind the radiator in the engine compartment at the front of your vehicle. The fan control module serves to switch the fan on and off at the appropriate time.

One of the byproducts of the combustion process is that your engine gets hot quickly. Friction from all of the moving parts inside also contribute to heat buildup. In order to prevent overheating, liquid coolant (“antifreeze”) is circulated through the engine block where it picks up some of the heat. The coolant is pumped out of the engine through rubber hoses to the radiator. There inside the radiator, the coolant flows through a series of small tubes, transferring heat to the tubes along the way. The heat is passed on to a matrix of wafer-thin aluminum cooling fins attached to the tubes, and air passing through the radiator allows that heat to dissipate into the atmosphere.

The radiator fan helps to draw air through the radiator to help in this process, especially when your vehicle is standing still. Some engines, especially older models, feature engine-mounted cooling fans. Most modern vehicles have electric radiator fan assemblies, each with a radiator fan motor at its core. The fan control module serves to turn the fan on and off, as well as change the fan speed depending on the operating conditions and air flow requirements of the radiator. The radiator fan control module uses inputs from several spots on the vehicle to determine the optimum speed to spin the radiator fan for cooling.