[busemans]

Did you vacuum the system? That is what pulls the freon and oil in, the vacuum. Once you get enough freon in and the pressure switch kicks, the compressor comes on.

The part you are turning should be a clutch assembly.

 

[busemans]

If you unbolt the compressor from the truck, is there an inspection cover that lets you clean the compressor inlet area?

I am not sure if the nissan compressors have this, i have more experience on jeeps and bmws, and i am not an ac guy so i am just going off my personal experiences.

I know on the bmw compressor, you could take the hose connections off the compressor and that let you clean in the compressor housing. I am not sure if you were supposed to, or not, but i did and it had all kinds of chunks in it that stopped the compressor. We cleaned it out and ran 98% rubbing alcohol through thr whole system (there are small cone shaped filters you have to clean to, in the lines) and then pulled vacuum and filled it with propane (propane is also a refrigerant, has a different r number) and pag oil and his 86 bmw was putting our 42 at the vents.

We ended up not needing to replace the compressor so maybe yours has little port or pieces you can unbolt and see if it can be cleaned and then maybe it will come back?