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10/10/2020

Five common faults of automobile air conditioner are solved in one breath today

Although experience is not necessarily reliable, in most cases, it is easy to do things with rich experience, and many detours can be avoided.


For the automobile air conditioning failure, it is the same truth. There are many kinds of faults encountered in the early stage. Even if we rely on experience in the back, we can handle 70% or 70% of the total.


In terms of automobile air conditioning fault performance, there are five common.


In the face of these five types of failure, I believe you have their own set of moves. Here only describes the conventional exclusion ideas for your reference.


01. The air conditioner does not work


Conventional thinking:


1. First check the system pressure and judge whether there is refrigerant in the air conditioning system.


2. If there is no refrigerant, refill it.


3. If it is found that the refrigerant content in the air conditioning system is normal. At this time, it is necessary to check the compressor (whether it can pull in normally, whether the power supply is normal, whether the signal line is normal, etc.), and also consider other components that affect the signal generation (such as air conditioning pressure switch, evaporation tank temperature sensor, air conditioning relay, etc.).


4. For the automatic air conditioner, the fault can be eliminated with the help of fault code.


02. Hot air from the left side of the air conditioner and cold air from the right side


Conventional thinking:


1. While checking the failure of the air door, pay attention to whether the warm air water valve can work normally.


2. For automatic air conditioning, it should also consider whether the air conditioning control module also has faults (although the probability is small, it can not be ignored).



03. Evaporation tank icing / air conditioning pipe icing / frost


Conventional thinking:


1. First, check whether the air conditioner drain hole can drain normally.


2. Then check whether the data and installation position of the evaporation tank temperature sensor are normal (replace and reset if abnormal).


3. Finally, refill the refrigerant (according to the actual situation, if necessary, replace the drying bottle / drying bag, expansion valve / throttle valve, and clean the air conditioning pipeline to ensure that there is no moisture inside. Make sure that the air conditioning system is clean and leak free before adding new refrigerant.


4. In addition to the above ideas, the influence factors of air conditioning control system (such as air conditioning panel, control unit, etc.) can not be ignored.


04. Intermittent uncooling and poor refrigeration effect


Conventional thinking:


1. First, judge whether the refrigerant is sufficient.


2. Observe the working condition of cooling fan (electronic fan) (whether high and low speed are normal). If it is abnormal, the fault points mostly occur in the fan relay, fan control module, fan circuit and fan itself, etc., which should be checked one by one.


3. If it is found that the system pressure is too high, the condenser should be checked and cleaned first. After cleaning, if the system pressure returns to normal and the refrigeration effect is obviously improved, it indicates that the fault is caused by poor heat dissipation.


05. The air outlet of the air conditioner has no wind / low wind / the wind direction cannot be adjusted


Conventional thinking:


1. After removing the dirt on the surface of air conditioner filter element and evaporation tank, the problem has not been solved, so the focus should be shifted to the operation part.


2. Remove the trim panel of the air conditioner control part, and determine the fault range according to the actual operation, and then observe the action of the corresponding damper motor / damper cable (such as motor does not act / action is stuck / pull wire is misplaced, etc.) to further confirm the fault location.



In addition to the above conventional fault phenomena, for those faults that do not take the ordinary road, we can analyze them by the method of reverse reasoning. The premise is that we must have a comprehensive understanding of the whole system of air conditioning.


As for reverse reasoning, we can analyze it from the following four categories.


1. Component class


It refers to mechanical parts such as compressor, condenser, evaporation box, drying bottle, expansion valve, damper motor, blower, warm air water valve, cooling fan, etc.


When the above parts work abnormally, they are mostly caused by wear, lock, surface dirt, blockage, leakage, sticking, imbalance and other reasons. As a result, there are no cold air, poor cold air effect, wind direction can not be adjusted, abnormal sound, one side of hot air and one side of cool air.


In this case, replacement is the most reliable solution when it is confirmed that the fault is caused by the mechanical component itself (non circuit reason).


Of course, in the whole process of replacement, we must avoid human errors in disassembly and assembly. After all, there are some strange air-conditioning failures, which are caused by these careless mistakes. The investigation is very hot!


2. Sensor class


As for the sensor, we can not only focus on the outdoor / internal temperature sensor, evaporation tank temperature sensor and air conditioning pressure sensor which are directly related to the air conditioning, but also ignore the sunshine / rainfall sensor, air humidity sensor, water temperature sensor, intake flow sensor, etc.


Once the sensor used to collect information (such as digital signal) is abnormal (such as data inaccuracy, damage, etc.), it will directly lead to the control unit to collect the error information and send the wrong execution command


(if the evaporation tank temperature sensor monitors the ambient temperature instead of the evaporation tank temperature, the control unit will make the compressor work all the time, which will lead to the evaporation tank icing and other phenomena).


In some cases, the air conditioning system will stop working due to the influence of engine load.


3. Module class


As the core control part of the air conditioning system, the air conditioning module communicates with other control modules while operating the air conditioning function. Once the communication is interrupted, there will be no information exchange. The most direct performance is the failure of some functions or the whole air conditioning system.