Does your fan blower motor work? On my 91 sub, the same fuse/circuit controls AC and blower.
I am assuming you tested both wires at your pressure switch, due to only one will have 12 volts when it is unplugged from accumulator.
SgtDel
aka "Andy"
www.delbridge.net
1979 Big 10 383 stroker
1991 Blu 'Burb 3/4 ton 4x4