I have a 2007 ford Taurus ac system running fine system charged ac clutch working but it's blowing hot air like the heat is on even vent mode checked hot cold temp switch in dash it is workproperly l

I had one the other day that the compressor was running and everything but was blowing hot. I sucked out the refrigerant and it only had half a pound in it. I dont know what was bulding pressure in the system but it way to low. How are you sure it is filled? Have you takin the vehicle to a shop and had it checked by a professional?

I recharged with one of cans from autozone but was close to full the large tube is cold like it should be

It needs to be filled with a machine to ensure correct level. You cant be accurate with cans. Thats the first thing i always make sure of when i have a a/c problem. I use the machine to take all the refrigerant out and put the correct level back in most of the time that it the problem. Its either overcharged from people just adding some or its undercharged from it leaking