The water pump provides circulating power for the heating system, delivers high-temperature coolant to the heat exchanger, heats the air blown by the blower in the air duct, and then sends the hot air to the cab to realize heating. Check whether the cooling water is sufficient and whether the thermostat works. The inspection method is to change the engine speed and measure the temperature difference between the upper and lower water pipes. Check the water pump and visually check the water circulation status. Check whether the radiator fan works for a long time, etc.
If the warm air is not hot after the water temperature rises, check whether the A/C indicator light on the air conditioning panel goes out and whether the throttle adjusting knob is turned to the hottest area when the warm air is turned on. If the throttle is not adjusted correctly, it is not hot to turn on the warm air. See if the temperature of the two water pipes is the same. If the two water pipes are not hot or have a temperature difference, it means that the coolant does not transfer heat to the heating box. You need to check whether the heating box or water pipe is blocked. In this case, we can directly remove the air conditioning filter, feel whether the warm air or cold air of the air conditioner has improved, and then directly replace the entire air conditioning filter.
The warm air of the car is not warm, or the hot air of the car comes up slowly. There are several possibilities. The first possibility is that the filter screen is blocked, causing the wind to be small and not hot. The second possibility is that the temperature controller failure causes the air conditioning system to circulate for a long time, or the water tank may be blocked. After we understand the principle of heating, we need to check which parts are faulty, which will cause the air conditioning heating system to fail.