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10 Reasons Why AC Contactor is Not Pulling In


Problem: My air conditioner or heat pump contactor contacts will not pull down. If I press in on the contacts with an insulated screwdriver the unit will run just fine. When I quit pushing down manually with the screwdriver the contacts open and my AC shuts off!  What is causing the contactor to not pull down and start my air conditioner?

Answer: We have this question asked many times during the air conditioning season. There are at least 10 reasons why the contactor on an air conditioner or heat pump will not pull in. Below I listed the 10 reasons. We also have a great YouTube video made by Word of Advice TV that explains these 10 reasons in detail. Many thanks to Word of Advice TV for making this informative, excellent video! If you have any questions please email us anytime We would love to help you out and earn your business! 

10 Reasons why the Air Conditioner Contactor is not pulling in: 

  1. The furnace power switch or the air handler breaker might be turned off. The furnace door might be loose and allowing the door safety switch to not be engaged. Make sure the furnace power switch is on and your furnace blower door is on tight.
  2. Make sure that your condensate pump safety switch has not tripped. Make sure that your condensate pump is working. If a condensate pump is not working then sometimes (if connected) the safety switch will go off and cause the entire AC system to shut down so that you do not get water damage in your home.
  3. You could have a bad thermostat or bad, loose thermostat wiring. Make sure that all your thermostat wires are good and tight.
  4. You could have bad wiring. I would recommend that you check all wiring to make sure that the insulation is good and there are no breaks in the wires. I have seen animals and weed eaters damage the thermostat wires and cause the fuse to blow on the control board or cause the low voltage transformer to burn up.
  5. You could have a bad 5-minute delay board. We sell some of these delay timers on the following page: Please click here if you would like to see some of the delay timers we sell. There are different makes and model timers, but they can go bad and cause the air conditioner to no come on.
  6. You could have a bad control board in the furnace or loose wires coming from the furnace control board.
  7. You could have a bad power saver switch that is installed by the electric company to control the time that your air conditioner is on in the summertime. There is a way to temporarily bypass this switch to see if this is the problem.
  8. You could have an open, tripped or bad HPS (High-Pressure Switch) LPS (Low-Pressure Switch).  If your unit is low on refrigerant charge then the low-pressure switch might be open or tripped. If your unit is dirty, over-charged, has a restriction in the system, or has a slow or broken fan motor (might need a new capacitor) then the high-pressure switch might be open or tripped.
  9. You might have a bad contactor. Either the contactor 24-volt coil can go bad, the contacts could be burnt or pitted or insects and dirty might get in between the contacts and cause the contactor to not work. We sell many different contactors on the following page: Please click here if you would like to see the contactors we sell. 
  10. You could have a bad low voltage transformer. Most of the time when a low voltage transformer is bad or burnt out it is caused by a low voltage short in the low voltage wiring. Most of the time it is in the low voltage thermostat wires where animals, weedeaters, or a breakdown of the insulation in the wires from being exposed to sunlight over the years. Check the thermostat wires for breaks, worn insulation, and grounding out where the wires travel through the furnace, air handler, or air conditioner’s frame. I have seen many ground out shorts and burnt out transformers caused by animals and worn wire insulation where the wires travel through the frame of the furnace, air handler, air conditioner, or heat pump unit.  We sell many low voltage transformers. Please click here if you would like to see the transformers that we sell. 

Below is an excellent YouTube Video that discusses these 10 reasons in detail. Thanks so very much to Word of Advice TV for making this great video!

You Can Search Our Site for More Troubleshooting Problems with Answers, Heating, Air Conditioning Parts and Supplies in the Google Search Box Below:

3 thoughts on “10 Reasons Why AC Contactor is Not Pulling In

  1. Thank you again for the ten reasons contactor switches don’t pull in.
    I followed your logical explanation and half way through had solved the problem. I certainly took much more time than a technician but got it running again, (after creating more problems for myself of course). I am calling YOU the next time because it is obvious you know your stuff and are willing to help.
    Jim Marquardt MD

    1. Thank you so very much for all your kind words and for taking your time to do write this nice comment! Please let me know if I can ever help you out. I hope you have a great and blessed day!

  2. Wonderful basket of how to!

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