Recently I had no AC.
First thought was that this was going to cost me $300 to $500 for an HVAC specialist to diagnose with special tester and recharge or something worse (BTW R-22 refrigerant is being phased out… and here’s why you might care.). But I didn’t jump there yet.
It was the hottest, muggiest day of the year, in my opinion, at 91+, tipping 42% relative humidity (think The Congo on a Pyschrometric’s chart).
Next, I simply observed the compressor fan not spinning while the thermostat was set to cool. I dove into researching common fixes, bought a multi-meter with capacitance function, and determined the root cause as a bad capacitor. Thankfully this was 2 days beforehand, and I ordered the capacitor to arrive before the hottest night of the year. A quick disconnect and re-wire (remember to note which wires go to Ground/Common, Fan, and Herm on the capacitor. And if you forget, an online search will get you there).
Final result- AC kicked on with cool air and I re-proclaimed air conditioning as the greatest invention ever. The End.