Heater Circuit Function

GF83.20-P-2003T Heater Circuit Function

Component Identification:

Function
The coolant pump (2) pumps cold coolant through the engine (M). The coolant absorbs the engine's heat and becomes heated. In vehicles with diesel engines, the coolant also flows through the exhaust gas recirculation housing (3). Shortly afterwards the heated coolant is routed through the heat exchanger (4), where the heat is dissipated to the passenger compartment air.

The heat exchanger (4) only has a specific volume of coolant flowing through it, which is sufficient to fulfill the heating requirement. The AAC [KLA] control and operating unit (N22) or comfort AAC control and operating module (N22/7) controls, by means of the heat exchanger shutoff motor (M16/32), the flow of temperature-controlled coolant to the heater heat exchanger (4). The coolant is routed via the coolant return, in which the coolant circulation pump (M13) is located, back to the coolant pump (2).