As I found in other cases, my A/C was blowing warm air and the outside unit was not running. I had my wife turn the thermostat on and off, only to hear a loud "click" come from the outside unit when she did so.
Here is how my case is unlike others I have read:
I pulled the cover and watched the single pole contact. It pulls in when the thermostat is turned on (I can hear a slight hum) and then pulls out when the thermostat is turned off. I have read other cases where the unit turns on