Why is my central air not kicking on?

Author: Lamont Daniel  |  Last update: Wednesday, April 16, 2025

If your home's central air isn't working at all, check the main electrical panel in your house. It could just be a tripped breaker or blown fuse. If that's the issue, just reset the breaker or replace the blown fuse. Your thermostat setting could be another reason why your central air isn't working.

Why is my central AC not kicking on?

It Won't Turn On

Check your breaker box for a blown breaker or tripped fuse. You may be able to fix this AC issue with the flip of a switch. If that doesn't do the trick, check the wiring in your thermostat. A loose or frayed wire could also prevent your unit from turning on.

How do I get my central air to kick on?

If these tips fail to resolve the issue, it's time to call for professional support.
  1. Check Your Thermostat. ...
  2. Check Your Air Filter. ...
  3. See if the Emergency Shut-Off Switch Is OFF. ...
  4. Check the Inside Unit's Power Switch. ...
  5. Make Sure the Drain Pan & Lines Aren't Clogged. ...
  6. Look for a RESET Button. ...
  7. Look for Icy Buildup.

What would cause my AC to not kick on?

Power issues: A tripped circuit breaker or blown fuse in your home's electrical system will prevent your AC from starting. Thermostat problems: Make sure you have your thermostat set to “cool” and the temperature is set below the current temperature in the room.

Why is the outside AC unit not turning on?

The main reasons your AC unit outside is not turning on could be something that has tripped the circuit breaker, something is blocking the fan's airflow, or the condensing unit is damaged. Other potential issues could be the thermostat isn't set correctly or the compressor could be malfunctioning.

Air Conditioner Not Turning On! Nothing is Happening! 10 Common Problems!

How do I reset my outside air conditioning unit?

It's a small, red button usually located on or around the unit. The button should have a clear 'reset' label. Once you find the button, press it for around three seconds and observe the AC. Check whether the AC kicks on immediately and if it doesn't, press the button again for another three seconds.

How do I force my AC unit to turn on?

Check Your Circuit Breaker

Locate your main circuit breaker and switch it back to the "On" position. Wait 30 seconds and turn on your air conditioner again. If it still doesn't work, you'll need to call a professional for help.

Why is my thermostat working but AC not turning on?

If your thermostat is set to cool but your AC isn't turning on, there could be several potential causes ranging from a simple tripped breaker to more complex refrigerant or compressor issues. Start with the basics, like checking the thermostat settings and power supply, and work through more detailed troubleshooting.

How do I know if my thermostat is bad?

7 Ways to Tell Your Thermostat Is Broken
  1. The Thermostat Has No Power. ...
  2. The AC or Furnace Won't Turn On. ...
  3. The Heater or AC Won't Turn Off. ...
  4. The Thermostat Reading Doesn't Match the Room Temperature. ...
  5. The Thermostat Doesn't Respond. ...
  6. The HVAC System Is Short Cycling. ...
  7. The Thermostat Forgets Programmed Settings.

How do you reset the AC when it is not turning on?

How to Reset an Air Conditioner in Four Steps
  1. Power down your AC. Turn off the power at the circuit breaker. ...
  2. Press the reset button. Most models require you to hold the button down for 3-5 seconds before releasing.
  3. Restore power to your AC. ...
  4. Listen and monitor.

What is the most common reason central air stops working?

The most likely reason your central air unit is freezing over is because of a clogged or dirty air filter.

Should I turn off AC if it's not cooling?

Yes, you should turn off your AC if it's not cooling.

Where is the reset button on central air unit?

Power down your AC: Turn off your AC unit and unplug it from the power source. This will ensure that you stay safe while working on the unit. Locate the reset button: Most air conditioning units have a reset button located near the outside unit. It is usually a small button located inside a small hole.

How do I get my AC to kick on?

Follow these steps.
  1. Step 1: Check the thermostat. Make sure that your thermostat is set to "cool" and not "heat" (if it's set to heat, your AC won't turn on no matter what). ...
  2. Step 2: Check the air filter. ...
  3. Step 3: Check the circuit breakers. ...
  4. Step 4: Clear the condensate drain.

How to tell if an AC fuse is blown?

Blowing the fuse cuts the power to the unit to prevent electrical damage. If your AC has shut down and won't start again, especially if you've noticed odd electrical behavior immediately before the shutdown, chances are the fuse has done its job and will need to be replaced.

What is the first thing to check when the AC stops working?

Check these issues when the unit won't kick on: Check the thermostat and adjust the settings if it isn't set to Cool and an appropriate temperature setting to call for cooling. Examine the house circuit breakers for the AC unit and reset any tripped breakers. Check the air filter and replace the filter if it's dirty.

How do you tell if you need a new thermostat?

Signs You Need a New Thermostat
  1. Heating or cooling system will not turn off or on.
  2. The temperature reading is incorrect.
  3. Recent spike in your energy bill.
  4. Frequent temperature fluctuations.
  5. Thermostat is 10 years old or older.

How to reset a thermostat?

Most modern thermostats will have a clearly marked reset button inside the panel. It's usually small and recessed, so you might need a pointed object like a paperclip to press it. For those wondering specifically how to reset air conditioner thermostat models, the process is generally the same.

How do I know if my AC is broken?

10 Signs Your Air Conditioner Needs Repair or Replacement
  1. Air Conditioning System is Blowing Warm Air. ...
  2. AC Thermostat is Not Working. ...
  3. Little Air Blows Out of Vents. ...
  4. Loud Noise Inside of the AC Unit. ...
  5. Strange Odors When AC Turned On. ...
  6. Not Enough Humidity Removed By the AC. ...
  7. Problems with the AC Are Occurring More Often.

Will thermostat cause AC not to turn on?

Signs of a Faulty Thermostat

AC Refuses to Start or Stops Suddenly: A thermostat that's not working correctly might fail to initiate the cooling cycle or might randomly shut off the AC. This erratic behavior can be due to electrical issues or miscommunication with the AC unit.

Why is my central air not responding to my thermostat?

Try checking the circuit breaker box or replacing the batteries. Bad wiring: The thermostat may be unresponsive if the wiring has gone bad. Remove the cover and check inside for loose, detached, or corroded wires. If you spot any problems, contact an HVAC technician for assistance.

Why is my AC unit not kicking on?

The easy explanation for your AC not turning on is a thermostat issue. Double check your thermostat is on, set to “cool,” and that the temperature is set to a few degrees colder than the normal ambient temperature of your home. You may also need to replace the batteries.

Can AC work without a thermostat?

The AC itself isn't detecting the temperature in your home, so it has to rely on the thermostat.

Where is the AC breaker located?

Circuit breakers can be found in homes, businesses, and industrial facilities. They are typically located in the main electrical panel, which is typically located in the basement or garage.

How to tell if an AC capacitor is bad?

A sure sign of a bad AC capacitor is a humming sound from within the access panel. Any humming noises indicate a problem with the air conditioning system or the components of the AC unit. Try turning the power on and off again to see if it was a one-time issue with the motor or a recurring problem.

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