Technical Ventilation air temperature knob problem

[percivall]

Hi all,
I have this problem with my 2018 Doblo. The temperature knob for ventilation does not turn all the way to cold, it gets blocked with a hard resistance. Thus the vent air is never cold - big problem in summer with the ac being a bit weak already by design.

Any ideas where the problem may be, how to solve, how to access the mechanics behind?

I will greatly appreciate any advice especially with the temperature going through the roof right now

Thanks
Jakob