You might try checking that wire for voltage when the ac switch is on, but you may have to short around the low pressure limit switch in the ac lines somewhere, pside core support maybe, to get power to that wire - it's at the end of a chain of relays and various safety switches (I think it shares the tranny od ground temp switch as one of the relay coil grounds). including the fan switch, too, in the compressor clutch power path.

On page 8=57 look at connector a45, also on the harness illustration on 8-29. It's a hair smaller than average .85BW wire, too. Note it's power path on 8-57, from the ac relay thru the low limit switch to power the magnetic clutch, the condesor blower relay, and the condenser blower. a45 looks like it breaks out of the wire bundle that has the wire for all the water temp gizmos, maybe 5" back on the bundle.

Look in the fsm at pages 8-29, at connector a40, listed on page 8-28 as condensor fan motor relay. Thats the fan infront of the a/c condensor/radiator, and I think it's relay is thereabouts.