Dash A/C issue

There is a relay somewhere that you need to replace to get the pump working if it has pressure, and the clutch isn't kicking on. Some systems have a high side cut out that keeps it from working if they put to much gas in it. Some just have a port that lets out the extra gas when it gets to high, this port will sometimes not reclose and you can never get the high side pressure up...If this happens it would let you put gas in , just shoot the gas out the broken pop off valve as you pump it in.