1, heater water tank blockage: The heater water tank of an automobile can actually be regarded as a miniature version of the radiator of the engine water tank, and its internal structure contains many tiny cooling pipes, so this structure, like the radiator of the water tank, is prone to internal blockage. After the blockage, the flow rate of the coolant in the heater water tank will slow down, and the flow rate will also decrease. Due to insufficient heating, the air-conditioned heater will naturally not be hot.
2. Thermostat failure: After the thermostat is normally opened, the coolant will circulate from the idle speed of the engine. If you use a car in winter in the north, the water temperature will be low for a long time, and the air conditioning warm air will naturally not be hot. As can be seen from the thermometer, the pointer is obviously lower than the normal scale. Therefore, if the warm air is not hot and the pointer scale of the water thermometer is still low, it may be necessary to check the thermostat.
3. Warm water valve failure: After the warm water valve failure, the opening of the electronic control valve is no longer controlled by the computer, and it is in a state of normally open, normally closed or fixed in a certain position. At this time, there is no coolant flowing through the warm water tank or the flow rate is uncontrolled, so the warm air temperature of the air conditioner is naturally uncontrolled.