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Radiator Cooling Fan Control Module: Description and Operation
The cooling fan module contains two internal relays that are controlled by the
ECM. The ECM controls two wires that supply a ground for the relays. Each control wire does not ground a separate relay; however, the combination of two discrete wires allow for different fan speeds. Eased on coolant temperature and A/C system pressure, the ECM can command low, medium, and high speed fan operation. If engine coolant temperature exceeds
105°C (221°F) at ignition Off, the two fans will run along with the auxilliary water pump for
two minutes.