92 elec clim cont prob no volt at pressure swtch

I have a 92 Bonneville SSEI. The temperature flashes when started. Compressor does not come on. Econ shows on display except when in defrost (but compressor still off). I checked fuses (driver, passenger, under hood). I have voltage at the AC fuse under the hood, but there is no voltage at the connector to the pressure switch. Any ideas on the most likely causes/cures? In the past the temperature would flash, but the A/C would work. Car has 200k+ miles on it. Was blowing cold before compressor wouldn't come on.

reset ecm by disc battary for 30 second and see what happen

It started functioning normally for about 1 or 2 minutes but would not blow cold. Then it reverted to staying on econ. Could the system be sensing low freon or is it sensing the compressor not coming on or other? Should I reset again, add freon and see what happens? Or do I first need to reset and check for voltage at the pressure switch?

put freon first make sure no leak and reset it
good luck

I reset and started putting freon in. It stayed on auto for a while, about 1 can went in. I reset and put in another can. This time it stayed on auto and seems to be fine now. Thanks for the help. Also put in leak sealant and ink. Saw bubbles coming from freon input valve, tightened the insert.