My Air conditioner stopped putting out cool air. The fan unit outside stopped turning. What would the problem be?

The unit is overheating and tripping the internal overload of the compressor. Clean outdoor coils.....check outdoor fan to see if it turns or is siezed......possible bad Start/Run Capacitor which is a very common failure on condensing units......possible bad fan motor need replaced! Unit compressor can be cooled with a water hose to get it to reset the internal biometalic high limit switch that is located in the hermetically sealed compressor!

If the fan is not working but the compressor is either your fan is bad or the start capacitor is. Also ck for burnt wires. The capacitor will be located under the access panel where the elect wires enter the unit. The capacitor will be a 3 wire combined fan and compressor or you will have two 2 wire capacitors the smaller will be the fan. It will have 5uf on it and 220v to 440v you can ck it by removing it (make sure the voltage is turned off to the unit turn the breaker off or pull the disconnect switch if you have one at the unit) and using an ohm meter (you can purchase an ohm/volt meter at a hardware store and some autoparts stores a cheap one will cost 10 to 15 dollars) Put the ohm meter on ohms and connect the leads to the posts on the capacitor after 15 seconds switch them the fmeter will slowly go up to 5uf on the scale if not its bad you can purchase one online or at a electric motor/rebuild shop. good luck