The part(s) or condition(s) listed below for the symptom Air Conditioner won't run are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
Air Conditioner Won't Turn Off? Air Conditioner Troubleshooting
Air Conditioner Remote Not Working? Air Conditioner Troubleshooting
Air Conditioner Loud or Noisy? Air Conditioner Troubleshooting
Air Conditioner Fan Not Working? Air Conditioner Troubleshooting
Air Conditioner Compressor Won't Run? Air Conditioner Troubleshooting
Air Conditioner Not Cooling? Air Conditioner TroubleshootingThe control board regulates the voltage to the compressor and the fan motor. If the control board fails, some components will not function properly or will not work at all. Control boards are often misdiagnosed; make sure to check more commonly defective parts first before replacing the control board.
The main control board regulates the voltage to the compressor and the fan motor. If the control board fails, some components will not function properly or will not work at all. Control boards are often misdiagnosed; make sure to check more commonly defective parts first before replacing the main control board.
The user control and display board allows the user to operate the unit by selecting fan speeds and cooling temperatures. If the board is defective, the air conditioner may be unable to run. If you've confirmed power it reaching the unit, it's possible the user control and display board is malfunctioning and will need to be replaced.
The selector switch directs voltage to the fan motor. If the switch is faulty, the fan motor may not turn on and the air conditioner won't run. To determine if the selector switch is at fault, try making selections on the air conditioner’s control board. If the fan runs intermittently after you press a button, replace the selector switch. Additionally, if there is any arcing or smoke coming from the selector switch, replace it.
Confirm the air conditioner is plugged in and there is power at the wall receptacle. If the wall receptacle is 120 volts, you can plug another small appliance into the receptacle to confirm there is power. For 220 volt units you will need to use a multimeter. If there is no power, confirm the circuit breaker has not tripped. Most air conditioners will have a separate breaker on the power cord plug. Confirm this breaker is not tripped. If the blower motor is working then the unit has power.
