Nissan Serena 2002 QRV.R Ltd. A/T (not converted, bought from Nissan Cebu Inc.)

Hello.

Our Serena's Aircon is using a digital climate control system. But ever since we bought this car (about a year ago, second hand), I noticed that the aircon's compressor does not shut off. It always stays on even if the temperature is always set to 28-30C (the temperature range is from 18-32C).

The hotter the temperature is, the blower just turns down, but the compressor never stops working, even though it is set at 31 or 32 (heater, hot air na ang lumalabas). The only time it turns off is when I turn it off by pressing the OFF button, or when i press ECON, but it does not turn on again until i press AUTO, so the air will start getting warmer.

The disadvantages? It's noisy. And it's definetly making the FC higher.
Nissans are known for their powerful aircons because of the big compressors which is of course putting weight on the engine, and it also eats up fuel.

I tried turning off the aircon or putting to ECONomy mode, the engine feels significantly stronger and lighter. I really think the aircon is hitting the fuel consumption really bad.

Our other cars' compressors turn off once it's cold enough.

Is this normal? or is there something wrong?

Theres an AMB button on the aircon and it shows normal temperatures. even if the AMB temperature is cooler than the setting, the compressor still turns on.

Thanks for reading.