Auxiliary Coolant Flow Pump
WARNING: This page is about a different car, the 2006 Mercury Montego, 2006 Ford Freestyle, and 2006 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.
Vehicles with auxiliary climate control are equipped with an auxiliary coolant flow pump. The auxiliary coolant flow pump is electrically driven and provides increased coolant flow to the front and rear heater cores. The auxiliary coolant flow pump is operational any time the ignition is in the RUN position.