It is a diode- J cars used diodes in compressor circuit. Since you can engage compressor by jumping relay, it is obvious your issue is upstream. Look at the high side transducer- you know it is a transducer because it has 3 wires (upside down near top of radiator) look for wires loose, broken, also ...

On trucks with issues after parts have been replaced, I always look for 2 orifice tubes in system- most all condensers have an OT in their outlet connection- yet rear air systems have their OT at the split (to rear) in the liquid line outlet--- so If you bought a new condenser- chances are real good...

Maybe a couple of weeks of vacuum....Never put anything in a system, that you can't get out. GM says to flush with refrigerant for that very reason...but you used a flushing agent that is a chemical degreaser and now you can't get it out.....Who ever sold you that flush does not realize the mess you...

Your Arcadia is well known for evaporator leaks--to fix is a dash pull- I've seen a few and done a few- about a 10 hour job. Look for green dye in the drain hose- under gas pedal under the truck.

My money is on the rear a/c lines leaking at a grommet most likely right at the rear wheel. Look for oily greasy leak,,,

It wasn't until 2002 model year for V-5 compressors went to double lip seals...

I've never seen the control valve leak-- always the case halves (belly leaker) scenario. Corrosion crawls up and under the cylinder halves o-rings and cause the leak. I take the compressor apart, sand down the corroded area and put new o-rings in, and have never had a comeback.

My money is on the shaft seal-- look for oily/greasy slinging oil traces/debris anywhere near the front of compressor- like on radiator hose or frame...they were famous for this issue. And holding vacuum doesn't always mean it can hold refrigerant......

Low side at 70?? Whoa Nelly- there-in lies your problem. Nothing cools at 70 low side- should be near 25-35. I suspect your variable compressor control valve is bad-- You can change it yourself- while it is on the car normally- just has to have system discharged.....

Can't you see the recirc door move? or hear the difference when you command it to move either way? I have also used light weight plastic wrap to see if it clings to recirc screen/filter when it should.....have had a few lack of air flow issues with plastic wraps clinging to the recirc entrance....