C4 air condition problem

I have a problem with my air condition of C4. The air condition is working fine when is at LO or 19...21C. When i turn the knob to 22..23 it start working on heat and blow warm air. This is happens only if i turn the drivers site knob. The passenger knob is cold at 22C
Also i noticed that when both sites are at LO temperature the passengers site blows colder air than the drivers site.
Does anybody had similar problem?