This is the rear command display of the 3-zones automatic airconditioning (called climatronic).
Here you can only select: temperature, direction of blowing, speed of ventilation.
In the display on the front, you can choose the front settings, and additionally airco on or off.
If you put the airo on at the front, then the airco will also work at the back.
I see that you have a first T5 (before 2010), so I don't know if you have a button at the front that will let you choose to synchronize all 3 zones of the aironditioning. Perhaps you can show me your front display?