There are lots of reasons your air conditioning unit may fail to work. Try this: 1.) Make sure your thermostat is turned on. 2.) Set it 3 degrees below room temperature. 3.) Turn on cool, not fan or heat. If the thermostat screen is blank, then the battery is dead. Replace the battery. If it still is not working, call for service. In the Little Rock, AR area Ski Brothers Heating and Cooling provides central heating and cooling, air conditioning service, and heating and ac service everyday. We are open Monday through Friday, 8 to 5 PM. We have great reviews, and will come to your rescue quickly!