2. Check whether the switch of the air door inside the air duct is not in place, so that the hot air cannot be completely turned on and the external circulation can be closed.
3. If the water temperature rises and there is no hot air, check the hot air solenoid valve.
4. Some models are equipped with electric heating wire for auxiliary heating. Check the safety and electric heating wire components.
5. Check whether the control mechanism of the warm air is not working well, and take a look at the temperature of the two inlet pipes of the warm air small water tank. If both pipes are hot enough, there is something wrong with the air volume control mechanism.
6, check the engine cooling system, take a look at the temperature of the two inlet pipes of the warm air small water tank, if both water pipes are cold, or one is hot and the other is cold, it is a cooling system problem.
7. This may be caused by blockage of the heater water tank or actuator problems.
The problem of air volume control mechanism;
1, the car's warm air uses a blower to blow the heat from the warm air small water tank into the cab. If the air volume is insufficient or the distribution of cold and hot air is not good, the heat of the small warm air tank will not be radiated, and the temperature of the warm air will not come up. At this point, first check whether the filter element is dirty or blocked, clean it, and replace it in time if necessary.
2. Check the operation of each gear of the blower to ensure that each gear has sufficient speed. If the knob is set to the warm air position, the air volume is large enough and the wind direction is normal, and the cold air is blown out, check whether the cable of the hot and cold air control flap in the warm air box falls off, whether the warm air impeller is damaged, whether the flap falls off, etc. After troubleshooting, the warm air will get hot.
Extended data:
Cooling system cycle:
The cooling system of automobile engine is a forced circulating water cooling system, that is, the pressure of coolant is increased by a water pump, so that coolant is forced to circulate in the engine. The cooling system is mainly composed of water pump, radiator, cooling fan, compensation water tank, thermostat, water jacket and accessories in engine block and cylinder head.
In the cooling system, there are actually two cooling cycles: one is the main cycle of cooling the engine, and the other is the heating cycle in the car. Both cycles are centered on the engine and use the same coolant.
Main loop:
The main cycle includes two working cycles, namely "cold cycle" and "normal cycle".
After the cold car hit the car, the engine gradually warmed up, and the temperature of the coolant could not open the thermostat in the system. At this time, only when the coolant circulates in the engine through the water pump can the engine reach the normal working temperature as soon as possible.
As the engine temperature rises, the coolant temperature rises to the opening temperature of the thermostat (generally after 80℃), and the cooling cycle begins a "normal cycle". At this time, the coolant comes out of the engine, passes through the radiator at the front end of the car, dissipates heat, and then enters the engine through the water pump.
Heating cycle:
This is a heating cycle, but for the engine, it is also a cooling cycle of the engine. The coolant passes through the heating device in the car, sending the heat of the coolant into the car and then returning to the engine. One difference is that the heating cycle is not controlled by a thermostat. As long as the heating is turned on, the cycle will begin, whether the coolant is cold or hot.
Reference source: Baidu Encyclopedia-Automobile Engine Cooling System