I added more 143a to the system the compressor started turning but slowly, the "dinky" gauge keep creeping up in the red, middle of the red, but did not over pressurize the system. I finished adding the 143a, small can, and disconnected the pressostat switch used the paper clip; the line to the evaporator(?) RH passenger side started to get cold immediately was covered in frost in no time the other line where the 143a goes in, closer to the driver, it did not sweat after 3 minutes. But after reattaching the switch the compressor started to run fast, normal, and then stop every 4 seconds then engage again, starting then stopping every 4 seconds or so. The air now is cool but not cold. Should I add another can of 143a or replace the pressostat switch? Thanks for all your advice.