Ac blows hot air. system is charged car only had 21,000 miles one person said it is the expansion valve and another said the oarafice tube may be clogged not sure where to start

Hi, the thermostatic expansion valve or txv is the metering device located in the liquid line. Its job is to meter refrigerant ( freon ) into the evaporator coil that is sealed by your fire wall and cools the auto down. This auto doesn't have the orifice tube that refrigerators use!! This txv would have to be plugged up at the screen to not meter freon into the system. I doubt its the txvalve. What I would do, is determine if the compressor is running and pumping freon through the system. You say it has a full charge, how was the determined? The compressor would have to be running. Its a pump under the hood that your serpentine belt goes around, and has what is called a clutch plate on the front of it. With the engine running, you can have someone set in the seat while you look under the hood. This pump has 2 aluminum lines coming out of it and the belt is on it also. Have the driver turn the a/c on cool high and you listen and look at the belt on top.It will be turning with the engine running and as soon as the a/c is turned on, you will hear this clutch engage on the front of the compressor, and loud click as this clutch will also start to turn. If it doesn't turn, the compressor is not working due to maybe a blown fuse, no freon and its off on its low pressure switch. If you know the compressor works for sure and the clutch is engaged, then you may have a problem in the expansion valve. Drop by a shop, go by auto-zone and have one of the guys look at the compressor and tell you if the clutch is engaging. You need to find this out. If its not, the fuse that's located in the electrical box under hood, its marked, will have a 30 amp fuse in it. I would personally drop by a auto shop and just ask them to tell you if the compressor and clutch is engaged when you turn it on. This would be the best thing to do, and then go from there. If its working and blowing hot air, you do have a internal problem and it will need service. You can't do this on your own, it takes special training and equipment to check. Consentrate on the compressor first and let me know what you find out. We can go from there, and figure this problem out. This a/c is new. Please keep me posted on this.
Sincerely,
Shastalaker7
A/C, Heating, & Refrigeration Contractor