Our AC has stopped giving us cool air a few times. A few months ago it did this I turned the breaker off, waited, turned it back on and it worked again. A few months later the same thing happened, I did the same thing again and it worked for 2 more months. Two nights ago it stopped giving cool air but turning it off hasn't seemed to do anything. The fan works, the thermostat works. Is it in need of coolant? Or could it be something else?

Could be any number of things. Do you have a multi-meter & know how to use it?