There are many reasons your car will blow cold air in certain areas. First check your freon level. It should be full because it's a closed system. If not then you have to find the slow leak usually at the schrader valve. Very rare you will have a leak on the line unless you have had a lot of work done to your car.

Your IHKA could be a reason. Commonly you're setting but you should know how to work the settings. Then it could be the IHKA itself. Not telling us the year/model/miles I don't know how old the part is but it is unlikely your issue.

The number 1 reason I've seen lately is the heater control valve. This would be your issue if your levels are good. You start loosing your a/c in different compartments until it completely fails. Failures are mostly do to gasket leaks inside the part. You can either buy a kit to fix it or buy a brand new part. Both ways are easy to do and will only take a few minutes of your time. The hardest part of it all is disconnecting the heater coolant hoses connected to it.

 

Listen to these guys! Warm air on one side and cold on another is a totally legit symptom of too low refrigerant