Air Conditioner Not Cooling, AC Troubleshooting, How to Test & Replace an AC Contactor, AC Relay

(HAZARDOUS) !!! Air conditioning repair CAN BE DANGEROUS so make sure you are familiar with safety precautions before you proceed. Disclaimer: All power must be shut off and capacitor discharged before repairs are made. We accept no responsibility for damages to you or your property. All repairs are at your own risk.
Is your air conditioner not cooling? Did your AC stop working and blows hot air?

If your AC is not blowing clod air and the fan in the compressor unit outside fails to start you likely have HVAC Contactor Problems. Do you notice the HVAC contactor buzzing/ humming noise or maybe the contactor not closing? Or maybe your AC won’t turn off because the contactor is stuck closed. These are all signs that you likely need to replace the contactor located in the compressor outside.

Air conditioner contactor cost depends if you are prepared to change it yourself or if you should have a professional. The part itself is relatively inexpensive ($50 to $100.00) but may cost much more to have a professional troubleshoot, test and replace it ($150 to $300 or more…) depending on the time of year and the time of day. It will be very expensive if you wait until the middle of the night at the hottest time of the year. AC contactors don’t just quickly go out they deteriorate over time and then fail.

If your air conditioning system is over 5 years old check the ac contactor annually and have a replacement purchased and ready to be installed as the signs appear. Of course this assumes you have the training and equipment to test and replace it which this video shows.

Well, you know your air conditioner needs repair you want to fix your own AC it may be necessary to test and replace your AC contactor. This video is part of a series on HVAC troubleshooting guide. This video is about air conditioner troubleshooting and how to troubleshoot and replace the HVAC contactor (some call it a HVAC relay). This video shows the process to check. This video also works for heat pump troubleshooting of the relay also.
Also see our video on How to Test & Replace AC Capacitor –