The scheme for switching on the main and additional fans of the engine cooling system with the Sirius D4 ECU: 1 - main relay; 2 - mounting block of relays and fuses in the engine compartment; 3 - relay for turning on the low speed of the fan; 4 - relay for turning on the high speed of the fans; 5 - electric motor of the main fan; 6 - fan control relay; 7 - ECU; 8 - refrigerant pressure sensor; 9 - air conditioner switch; 10 - coolant temperature sensor; 11 - additional fan motor