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

Model All (4xWD) 

Model All (CAR) 

Example illustration on 2-zone automatic climate control 

Fig 1: Circulation Pump Components Location - Model All (Car)

Courtesy of MERCEDES-BENZ USA

Overview 

This document contains information on:

• General 
• Function requirements 
• Function 

General 

The coolant circulation pump (1) delivers coolant through the heater core and combustion engine in vehicles with a combustion engine.

The coolant circulation pump (1) delivers coolant through the capacitor, high-voltage PTC heater and heater core in vehicles with an electric motor. The control for climate control directly actuates the coolant circulation pump (1).

The coolant circulation pump (1) may be located in various positions around the engine compartment depending on the model and equipment installed.

Function requirements 

• Circuit 30 t ON

Function 

The following functions lead to actuation of the coolant circulation pump (1) (depending on the model and equipment installed):

• Air conditioning:

  The coolant circulation pump (1) supports 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.

• Stationary heater:

  The coolant circulation pump (1) delivers the heated coolant through the combustion engine, heater and heater core when the stationary heater is active.

• Pre-entry climate control:

  The coolant circulation pump (1) delivers the coolant through the high-voltage PTC heater and heater core when pre-entry climate control is active.

• ECO start/stop function:

  The coolant circulation pump (1) delivers the coolant through the combustion engine and heater core during "engine stop".

• Exhaust gas turbocharger run-on cooling:

  The coolant circulation pump (1) delivers the coolant through the exhaust gas turbocharger for a certain period of time after the engine has been switched off in vehicles with turbocharger run-on cooling.