Diagnostics of climate control becomes necessary if, during the operation of the air conditioner, you notice sudden temperature changes inside the car, as well as a pungent smell, vibration and noise, or the air conditioner power indicator gives false information. If the interior air is not warm enough or cold when the air conditioner is on, this is also a reason to check climate control. In the course of diagnostics, an expert checks the condition of the compressor drive belt and bearing, the condition of the hoses and lines, connections, the serviceability of the refrigerant circulation in the system, the presence of oil leaks at the joints, the condition of the condenser surfaces, the cleanliness of the evaporator, the operability of the heater fan and the cooling fan.