Chevrolet Repair: AC question, pressure gauge, pressure sensor

Question
Once again CJS thank you for your time and effort. It is greatly appreciated. I do have a pressure gauge and it reads at 45 psi when hooked up to the low port. While trying to figure this problem out today i noticed that now the ac clutch does not engage anymore. I also noticed that the silver canister (accumulator? correct?) does not get cold nor do any ac pipes while ac is turned on. Do these symptoms tell you anything? I'm tempted to change out the accumulator and the pressure sensor.  

Answer
Hi JK,

I think you are low.  Do you have a leak?  The compressor won't come on if the pressue is too low.  The silver can is the accumulator, and that should be cold to the touch.  Even with the AC off.  If that is warm, you are low.  Many mechanics, simply touch that and tell you immediately you need a recharge.  

"Normal" pressure readings on low side:

System at rest: ~100 lbs
Refrigerating: ~30-40 lbs (remember cut off switch opens at 28 lbs, so you may want to aim high)

Put in one can, with the system set to 'ON' MAX.  May take two cans, if you are way low, to get the compressor to come on.  At MAX AC, the compressor should stay on.  

Let me know if this doesn't work.

C J S