Why does the car vent suddenly blow hot air?

[BriellaLee]

The reasons why the car vent suddenly blows hot air: 1. The external circulation is turned on, as the incoming air passes through the engine compartment and carries the heat from the engine into the car through the air distribution box, causing the vent to blow hot air; 2. The car's heating system is turned on, leading to hot air from the vent. Simply adjust the vent's circulation mode or turn off the car's heating system switch. It is normal for the vent to still blow hot air after turning off the air conditioning. After turning off the air conditioning, just set the temperature to the lowest and switch the air conditioning to internal circulation mode. The car air conditioning cooling system consists of a compressor, condenser, receiver-drier, expansion valve, evaporator, and blower.