I have been working on our daughter's 2004 Yukon Denali's A/C.
After sorting out the actuators for mode, temp, and re-circulation, I charged up the system with about 3#s of R134a.
The output temp (55-60F) seems fine for the moderate temps lately (low 80s, 40-50% humidity). While driving around today, the center outlet temps were around 40F.
At idle - Low side 24-45, High side 115-170psi. According to the GM service information, the pressures are within specification.
What puzzles me is the compressor is cycling ON/OFF.
The Autel scan tool displays: A/C pressure low, A/C withheld; when the compressor is OFF.
Is this a normal operating condition for a orifice tube system?
I've yet to look for the leak and why the rear A/C system isn't responding. I suspect Class 2 comm for the later.
I'll say one thing, if someone wants to learn about automotive mechanics, advise them to buy a car/truck that needs a lot of 'love'!