Coolant circulation pump, function - GF83.20-P-2102-01M

Function 

The quantity of coolant circulating through the rear heater core with the engine running depends on the coolant pump. The coolant circulation pump ensures that a uniform quantity of bubble-free water flows through the rear heater core even at low engine speeds. The coolant circulation pump is controlled directly by the rear A/C pushbutton control module.

Control of coolant circulation pump by rear A/C pushbutton control module