Auto Air Conditioning & Heater Repair: air condition, refrigerant charge, pressure switch

Question
The  aircondition use to blow real cold air then it would go off amd blow  hot air and later would come back on and blow cold air again  now the compressor will not come on.please give me a answer.Thank you Carolyn Mc Neil

Answer
Carolyn,
How long was the gap of time between it blowing cold and shutting off, and coming back on? From your desription, the first thing to come to mind is that you have a leak in your system that has caused you to have a low refrigerant charge.
If this is the case... what is happening is... as your compressor is turning and woking normally it creates a high side and a low side. Inside your low side line, you have a pressure switch that shuts down the compressor if the pressure drops too low. If you have a leak it would cause your low pressure to drop way too low. Your pressure switch would open up and shut off your compressor. Withthe compressor off, the pressure equalizes between you high side and low side, closes your pressure switch and it begins blowing as it should.
I recommend you check your refrigerant charge. If it is low, I then recommend you take it to have the leak found and repaired. If you choose not to have it found and repaired, you can just charge it back up, but know that you will be doing it again sometime in the future.
Thank you for the question, I hope I was of some help. If I can be of any more assistance now or in the future, do not hesitate to ask. Please remember to rate this answer, and good luck in everything