The auxiliary or additional water pump is not the most common automotive feature. However, it's a welcome augmentation on cold days. The function of this part is to cycle extra coolant liquid to your vehicle's heater. This allows quicker and more powerful cabin heating than in systems lacking an additional water pump. Unlike most primary belt-driven water pumps, these parts often use electric motors to drive their pumping mechanism. Over time, the components in these motors along with the mechanical parts of the pump itself might begin to degrade, diminishing the function of the heater and necessitating replacement. Ensure your comfort in cold weather by getting your faulty additional water pump switched out before winter comes.