Do not cover the aperture of the sunlight sensor and do not treat the sensor with glass cleaner.
The temperature sensor located in the passenger compartment should also not be covered with any objects or sealed.
If you do not use the air conditioner for a long time, you need to turn it on from time to time to lubricate the internal components of the system.
Note: The refrigeration unit of the air conditioner stops working when the ambient temperature is close to zero, so turn on the air conditioner only on warm days.
Refrigerant
Fill the air conditioner only with new refrigerant HFC 134a (R134a).
If the cooling efficiency of the air conditioner decreases, contact a service station.