Hello,
If I make a mistake, please moderate the posting.
My engine is equipped with a Delphi v5 needle compressor original code 51810417 (model borrowed from Opel), it does not have a pressure solenoid valve, it has a mechanical valve.
Symptoms and tests:
Do not breathe cold air
Couples and after some time disconnects (enters protection)
Electric fans do not start.

Freon weighed 630 grams
It had pressure, vacuum test ok, but when we connected the needle the compressor did not make the necessary pressure, one of the mechanics said that the compressor was running.
After the documentation I read about this solenoid valve, etc.,
I looked for the mechanical valve, bought --- removed the freon --- replaced the valve - put the freon - and then I enjoyed the cold air.
I'm attaching a picture of the valve
Delphi code 0425009/0 (has a red head)
0425010/0 (..... brown)
Both I believe work at close pressure and were not available to order.
The operator gave me the equivalent.
Thermotec part code ktt060023

I hope you don't run into this problem.