I replaced my A/c fan twice,got the compressor checked and it checks good but on 1996 Nissan Pathfinder

It still not working, what could be wrong with it.

A/C compressor not working or just the fan,, or both?
I had them both checked the compressor is good and fan was replaced twice but it's still not working. Can it be the actual on/off switch ?
Possible,, has the blower resistor been checked? If not have that done.
Can you tell me where it's located , I can't find my Repair book . By the way Thank you for your help it is greatly appreciated .
It is mounted near the blower itself but this really needs to be checked out by a competent mechanic which it seem like you need to find! No luck so far it appears! ALL fuses ok?