What is the reason for poor heating of KIA k2?

Nine times out of ten, if you see the following phenomena, you can completely confirm that there is fog on the glass when driving, and it is not easy to clean it. 2. If you open the floor glue, you will find that the underground is very wet and even has water. 3. Check the antifreeze. If the liquid level is very low, and there is no water accumulation solution below the long-term parking position, 1, find 4S to claim compensation during the warranty period. 2. After the warranty period, just find a roadside repair shop to repair it (parts of heater water tank 180 yuan, working hours around 200 yuan). Dismantling the instrument panel is very troublesome, at least 1000 for 4S).