I've got a 2011 Aveo LT, AC is only cooling about 10F from ambient. I've evacuated it and it held vacuum. I refilled it using around 500g of R134a. on my gauges I get around 54psi on low side, 180 on high. Outside temps were around 78F and vent temp went to around 68F. Radiator fan only kicked on when engine temp got high from idling.
Pressure switch seems to work properly
AC Clutch turned on and off with pressing on/off the AC button or pulling out the AC relay under the hood
BUT one thing I noticed is that it doesn't seem to put any load on the engine. On other cars, when AC clutch latches you can feel/hear the engine load increase and trying to compensate.
I suspect the compressor is bad or the control valve in the compressor is faulty. because of the no load while the AC is engaged. I'm at the point where I might buy a new compressor, a new expansion vale and a seal kit to replace all of them while I've got it all opened up.