2011 silverado

[Odinvalknir]

For about a week or 2 the air would drop off thru the vents and sounded like it was blowing inside of a box down by the floorboard. At the same time the accumulator would totally freeze and be covered in ice. If I turned off the AC for a bit and let it all melt thebac would work again. Today the AC stopped working totally, compressor not coming on, no cold air, accumulator is hot. Checked pressure and system is still pressurized to it's normal psi. On older Chevy's I've owned the low pressure switch was on the accumulator, but not any more apparently. Any ideas on where to start?

[JohnHere]

It sounds to me like the system has a leak someplace, which caused the problems you experienced a couple of weeks ago, and now the total system shut-down. Realize that static pressure alone won't tell you how much refrigerant is in the system (if any). I'd start by having the charge recovered and weighed. My guess is that most of the refrigerant has leaked out, not uncommon given the age of your vehicle.

[Odinvalknir]

Oddly enough, the AC is working again today. I cranked my truck this morning, and just as a hopeful thought turned on the air. It's cold again. What is going on? Lol possibly an electrical problem somewhere?

[JohnHere]

You could just leave it alone for now and see whether the problem recurs. If it does--and I suspect it will--the refrigerant charge could be right on the cusp of being barely sufficient to run the compressor, and sometimes not. The accumulator icing-up also suggests that some refrigerant has leaked out. The only way to know for sure is to recover and weigh the charge. If it's low, it could just be a very gradual loss (possibly from the compressor shaft seal, which normally leaks a slight bit) since the truck was new. Now that the system is running again, I'd also connect a good manifold gauge set and evaluate the high-side and low-side pressures. Knowing the pressures will give additional clues about the system's present state. If no obvious leaks can be found, an evacuation and recharge might be all that's needed to get the system running for a few more years.