I have an XJ that we recently purchased and have been refurbishing it and have come to the A/C. Went and serviced out the compressor oil, vacumn pumped, found no power to clutch. and jumped clutch to finish charging the system. Two pounds Freeze twelve.
Checked into web browersers and found CKF.com, I recently read abovetimberlines thread on A/C trouble shooting on the what nots. Very useful and performed all the inspections, relays, temp switch, I did trace out and power the blue/w stripe on the EPC side relay and the thing works. So there are no breaks or bare wires, the two wire temp switch plug was jumped and still no power. The thread I read earlier said the blue/w stripe wire is the one that is off the ECP and is there perhaps some thing other than the temp switch>? I've was taking a break to see if some one else has ran across this rare situation? Big Bess P.S. I did follow the other points to check out such as the low pressure switch (ok), no high pressure switch on 89 cherokee!

 

Are you sure on the pressure switch from my understanding it is called the clutch cycling switch it keeps the pressure between 25 and 35 lbs If you are over 35 lbs and the switch is open try taking some of the charge out and see if the switch closes it keeps the evaporator in the cab from freezing. You dont want liquid refrigerant to get into the compressor. The vapor or low pressure side goes into the compressor and is then a high pressure vapor that condenses to a high pressure liquid that goes through the expansion valve and flashes to a low pressure vapor that absorbs the heat in the cab (superheat) then goes through the compressor still as a vapor and as the heat is pulled out of the refrigerant (subcool) outside it condenses to a liquid. You are not adding cool you are removing the heat with the refrigerant that is why a proper charge is necessary and the pressure switch is there to protect the system. The oil is mixed with the refrigerant to protect the only moving part the compressor.