A/C button is on and the recirculation is set to inside. What can be the problem? This problem hasn't occurred last summer, could it do anything with the dealer heater core install?
Thanks in advance!!

Why would you be on recirc? I only use it when it's extremely hot or there is very much dust flying around. Even driving in the southern USA or Mexico I seldom use the recirc!
To me it sounds as if there may be a problem with the dampers in the system. Maybe the core installers screwed something up?

 

I had a 06 Chrysler 300c 5.7L. Driver side A/C was blowing warm/hot air while the passenger side was cold. I would hear a clicking sound when turning on the heater/A/C, and learned it could be a stuck actuator door. Electric servo motors do all the blending now and they do fail more than they should and fixing them is not for the novice. You need to get the HVAC codes first then if it is deep in the system disassemble the entire dash to gain access to the HVAC unit. It was not cheap to fix, and it failed again after a year.

Don't know if the Passat uses the same type of system.

 

Did you ever get this problem diagnosed? I have a 2015 Passat TDI that is doing the exact same thing.

 

Have you tried any diagnostics or scanned for codes? If a servo is not working, there generally will be a convenience system trouble code.

 

This could also be a symptom of insufficient refrigerant. Measure loan and high side pressures with a gage set and compare against the R134a charts.