① Refrigeration system
Refrigerant: whether there is a bubble phenomenon by a pipe optic liquid microscope, and a slight bubble or clear air without bubbles indicates that the refrigerant is abundant, and the foam indicates that the refrigerant is insufficient, and the refrigerant needs to be supplemented.
Pipeline: check whether there is leakage at each joint at any time. It is normal if there is no oil stain around the joint. If there is oil stain, it means there is leakage and it needs to be checked and repaired. When the pipeline surface is damaged, the protective layer should be added. The pipeline shall be protected from moisture and dust during maintenance. When disassembling components and pipelines, the pipe head or pipeline shall be sealed in time to avoid dust and moisture entering.
When the cooling effect of the air conditioner is not good, check whether the heater water valve is closed. If the two black hoses of the heater are hot, close the heater valve before using the air conditioner.
Regularly check whether the drive belt is too loose and whether the inner bearing of the tensioning pulley operates normally.
The belt should be checked only after the engine stops. Use two fingers between the two wheels to press down 7-10mm. It is better to have a little elasticity. The belt needs to be replaced in case of serious wear.
Condenser core: there should be no foreign matter on the surface to hinder the heat exchange. When there are foreign matters on the surface, the surface dust should be gently washed away with water. Pay attention not to use high-pressure water or gas for cleaning.
Fan motor: check whether it rotates normally and whether the air volume decreases.
Evaporator environment: always keep the cab clean, do not pile up a lot of debris, so as not to hinder the air circulation.
Evaporator core: whether there is dirt on the surface and filter screen, if so, dust or debris on the surface should be removed immediately.
Fan motor: check whether it rotates normally.
⑤ Wiring harness
Check whether the clamp plug is loose and whether there is friction between the clamp plug and the car body. If there is such a phenomenon, the clamp plug should be fixed and insulated.