Balky A/C

[PeteCal]

I have a 1984 Chevy Celebrity with a balky air conditioner. I retro fit it last year for R134.

A few days ago, the compressor started cutting out now and then. Now, the compressor won't run at all. I have found that there is +12 volts going right to the compressor clutch "plus" terminal. If I put a ground on the "minus" terminal, the clutch engages, the compressor runs, and the A/C cools the car.

There seems to be two pressure switches, one on the high side and one on the low side. Both seem to be operating correctly because the +12 is getting to the clutch. The "minus" side of the clutch has a short wire on it that goes directly to the back side of the compressor. I gather that there is another switch inside (pressure switch maybe?) the compressor.

I hooked up some gages to the low and high side. The outside temperature was 87F. With the A/C turned on, engine running, but the compressor not running, both the low and high side were at ~100 psi. I put my ground wire on the minus side of the clutch so the compressor would run and watched the pressures. The low side went down to about 35 psi fairly quickly and held there. The high side went up to 275 psi in a few minutes and held there. Inside the car, it was cooool even with the windows down.

From what I have been able to learn elsewhere, everything is as it should be except for needing the ground wire to bypass whatever is inside the compressor.

So, my questions are:

(1)what is inside there on that wire, another pressure sensor?
(2)If so, why doesn't it close and make the circuit to ground?
(3)If it is because the switch is faulty, what harm can I do if I just bypass it with a wire?
(4) What other alternatives are there,

I don't want to put any $$$$ into this car, I will put it up for sale soon as my daughter's car comes in.

Thanks in Advance.

PeteCal