A/C pressure testing issue

[kuroyabumozu]

I was trying to check the A/C pressure because there’s no cool air coming out of the fan, but somehow the A/C compressor clutch was still engaged when just turned on the car, that indicates there’s refrigerant in the system, but shuts off and on in the interval of 3 mins. Also while the car is off, I tried to check the pressure…. Somehow I can't for the High-Pressure side, it would just splash the refrigerant out, and the Low-Pressure side was able to hook up, but no reading at all.
Could someone please explain what’s wrong with my A/C system?

ChatGPT's response?

[tbirdtbird]

You have given no indication of make/model/year/mileage.
"but shuts off and on in the interval of 3 mins."
This sentence makes me believe that the charge level is low either due to an outright leak or seasonal losses.
The place to start is to sniff all joints, the evap drain, the evap coil and condenser coil as best you can with an electronic sniffer. Pay attention to the comp shaft seal, this is a wear point.

Assuming you find no leaks , have it evacuated by a pro shop, then recharge to under-hood label specs.
Should a leak be found, fix it and then recharge as above