What happened to the warm wind in Elantra?

The reasons why Elantra warm air is not hot are: 1, and the cooling system lacks coolant; 2. The heater water tank is blocked; 3, warm water valve failure. When using warm air, the front windshield is prone to fog when the temperature difference between inside and outside the car is relatively large. As long as the direction of the warm air is adjusted to the position where the windshield is blown, the fog can be removed in a few minutes. Elantra is a model owned by Beijing Hyundai. Its length, width and height are 4495mm, 1720mm and 1425mm respectively, and its wheelbase is 2610 mm. It is equipped with 1.6 liter and 1.8 liter engines, of which 1.6 liter.