Circulation Pump, Basic Function - GF83.40-P-2020A

Model all (CAR) 

General 

For vehicles with a combustion engine, the circulation pump delivers the coolant through the heater core and the combustion engine. On vehicles with an electric motor, the circulation pump delivers the coolant through the condenser, the high-voltage PTC heater and the heater core. The control for the climate control actuates the circulation pump directly.

The following functions can request actuation of the circulation pump (depending on model and equipment installed):

• Climate control

  The circulation pump is used to support the coolant pump when the engine is running. When the residual heat system mode or the heater booster function is switched on, it pumps the coolant through the combustion engine and the heater core.

Location 

Depending on the model and equipment installed, the circulation pump (1) may be located at different positions in the engine compartment.

Shown on 2-zone automatic air conditioning 

• Stationary heater

  When the stationary heater is switched on, the circulation pump feeds the heated coolant through the combustion engine, heater unit and the heater core.

• Pre-air conditioning

  When the pre-entry climate control is activated, the circulation pump delivers the coolant through the high-voltage PTC heater and the heater core.

• ECO start/stop function

  At "Engine stop" the circulation pump feeds the coolant through the combustion engine and the heater core.

• Turbocharger afterrun cooling

  In diesel vehicles, the circulation pump is required for the turbocharger afterrun cooling function.

Fig 1: Circulation Pump Components Location - Model All

Courtesy of MERCEDES-BENZ USA

Function requirement 

• Circuit 30t ON