A few months ago everything worked and I never had any problems with A/C. But after not using the car for a couple of months, A/C stopped working. It blows the room temp air. I tried to see if hot air still blowing, it is. After switching to A/C i can hear how system changes and it sounds different as before. But not cold air is coming. First thought was that it leaks and need to refilled the system. but tester showed that pressure in the system around 100pci. what can it be? thank you.