Its been a while since I've had functioning ac in my blazer, so I rented a manifold test gauge and checked the pressures.

Here are my results:

Engine off/static test-

Low side: 20 psi
High side: ~25 psi

Engine on, idling, ac and fan on max-

Low side : 0 psi
High side: 75 psi

Engine on, @ 1500 rpm, ac and fan on max

Low side: low side gauge showing vacuum: 10 hg
High side: ~85 psi

According to this PDF from sanden ac compressors, I might have a restriction somewhere in the system, and low on refrigerant too? I need some help interpreting my test results, thanks for the info guys,

 

No A/C guys here?