2001subaru Outback A/C issue (I even donated!)

I have a 01 outback wagon with the H6 (6cyl) automatic with almost 90k miles. I purchased on ebay w/83k miles so I dont know the service history other than no accidents and clear title.
My a/c was very intermittant this last summer.
I took it to a shop to evacuate the 134a I took it home and then connected to a vacuum pump and it held the vacuum for 20 min. I put approx 24oz of 134a back into the system and noticed that the compressor clutch engauged for about 5 seconds and wont re-engauge. My low and high side readings are equal at approx 75 psi (which I think is normal when the compressor is not cycling) My feelings are that it could possibly be the press cycling switch located in the reciever dryer but I am not sure. Just would like all options before I evac and recharge again.
NOTE: I took it to a small shop and with out asking me, the mechanic ran a jumper wire from the pressure cycling switch to the compressor. When I got the car back my a/c was cold and seemed to work great. What I found later was that the compressor was running all the time. I took it back 2 days later and they repaired the wires and refunded my money. When I picked up the car after many apologies they said they thought it was a faulty expansion valve. I purchased a exp valve from subaru and installed it and just did the evac and recharge that this letter started with.