How do i keep the air circulation open all the time for fresh air? Possible?

 

I guess I cheat a little bit. I like to get fresh air in the car and you can either: 1) let the A/C-heat work all the time which will pump a certain amount of air around the car, or 2) open the sunroof to the vent position and then if you give one of the back windows a quick jog, it will open the window around one inch and that will get you a nice breeze of air moving through the car and it is not that much noise. Of note doing #2, if you want the breeze on the driver, open the rear passenger window. If you want the breeze on the passenger, open the rear driver's side. As for keeping the car in the recirculate mode, I do not believe that is possible.

 

Assuming your x351 is fitted with an air quality sensor which it probably is, and when your Climate control system is set on automatic, the sensor controls the "automatic recirculation" of air. The air quality, i.e. air pollution and humidity, is a predetermined setting you can adjust in Settings. If it is set high, you may have the system always closing off outside air and recirculating cabin air.
Pressing the recirculation button will deactivate automatic recirculation. Please read your vehicles manual. My XJ is a 2014.