Temperature sensor for stationary heating in the cabin! Where?

Drive an MP3 Bj 2011 and can’t control the cabin temperature exactly, both with normal heating and with the stationary heating. Control so far only with manual rotary switch white ,blue red. With the same setting the temperature varies. Also, I often have to turn high to animate the warm air. Therefore, my question is there a sensor in the cabin? Bzw. with the MP2 I was able to adjust stationary heating via display this is also possible by software feeding. ng heats the cooling water as well!