Clear some things up. What vehicle is the condenser and evap from? Is there by any chance still an orfice tube in the evap? You mentioned you tried a new expansion valve but you also mentioned a pressure switch. How about some photos of the system. make sure you step back and include an over all vie...

You are testing my memory which I probably will fail. The transducer has 2 wires. Tan goes to the amplifier. I think it is an 18ga wire. The other gets grounded and is a 20 ga wire. I am guessing the size of the wires but the tan one is marked 18T and the other is marked 20B

To drain it, remove it from vehicle and turn it up side down. You should rotate the shaft by hand also. To fill it, pour oil into suction port and also turn shaft.

I sort of remember GM had a problem eating compressors due to the route the lines were run. It seems (if I can remember) that the suction line cause liquid to enter the compressor and ate the valves. You might try to contact GMTech as he should have more info on this.

That you tube video has some bad info. Most gauge sets do not have a schrader at the yellow hose for purging. You would crack it loose to purge the hose. Also, put the blower on high speed not low speed. The you tuber was adding refrigerant as a liquid. you can not do this unless you are charging a ...

Sorry for the long delay of answering your question. If the high side is reading zero, the high side hose fitting probably is not opening the Schrader valve. When you get the system running, by unplugging the blower motor the low side should read 28 to 32 PSI

Forgive my ignorance but what is a BBC?

What is the high side reading while the system is off? After a few minutes, it should read the same as the low side. keep the high side hand wheel on the manifold closed, place your R12 in hot water, and you will get the R12 to flow into the system. I think that system requires 3 1/4 lbs of R12. You...

b] The dealer's service writer said there would be no problem driving the car while we wait for parts, as long as we didn't turn the AC on. Okay, it's not summer anymore, but doesn't the compressor want to be on in DEFROST setting? Supposedly the system won't try and turn on the compressor if it's l...

If it were mine, I would disconnect the 12 volts going to the compressor.