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 pollution around the joint. If there is oil pollution, it means there is leakage, which needs to be checked and repaired. When the pipeline surface is damaged, the protective layer shall be added. The pipeline should be moistureproof and dustproof during maintenance. When removing parts and pipelines, the pipe head or pipe should be sealed in time to avoid dust and moisture entering.
When the cooling effect of air conditioning is poor, check whether the warm air water valve is closed. If you check the two black hot air hoses, you should close the warm air valve before using the air conditioner.
Regularly check whether the drive belt is too loose and whether the inner bearing of the tension pulley is running normally.
Check the belt only after the engine stops. Press down 7-10 mm with two fingers between the two wheels. It is better to have a little elasticity. The belt should be replaced when it is seriously worn.
Condenser core: there should be no foreign matters on the surface to hinder heat exchange. When there are foreign matters on the surface, the dust on the surface should be gently washed away with water. Attention should be paid not to use high-pressure water or gas for cleaning.
Fan motor: check whether it rotates normally and whether the air volume decreases.
Surrounding environment of evaporator: always keep the cab clean, do not pile up a lot of sundries, so as not to hinder the air circulation.
Evaporator core: whether there is dirt on the surface and filter screen, if yes, the surface dust or debris should be removed immediately.
Fan motor: check for normal rotation.
⑤ Wiring harness
Check whether the clamp plug is loose and whether there is friction with the car body. If there is such a phenomenon, it should be fixed and insulated.