Why is my AC not turning on?

Author: Ashlee Mosciski DDS  |  Last update: Wednesday, April 2, 2025

There are a number of reasons why your AC unit may stop working unexpectedly, including electrical problems, blockages, thermostat issues, and more. Troubleshooting includes checking your circuit breakers, thermostat settings, and replacing your air filters.

Why is my AC not kicking 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.

How do I force my AC 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.

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 do I reset my air conditioner?

Reset the AC Using the Isolation Switch

The isolation switch looks like an ordinary light switch with a knob. Once you locate it, turn the knob to the off position and leave it for at least 30 minutes up to an hour. This will allow the electrically operated components in the AC to reset.

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

How long does it take for a AC to reset itself?

Your air conditioner's internal circuitry needs some time to reset after you turn it back on. This can take approximately a half-hour, so sit tight for about 30 minutes. How to reset air conditioner after power outage at the thermostat. After 30 minutes have passed, turn your air conditioner back on at the thermostat.

Can resetting the breaker fix AC?

In the majority of cases, your AC system will return to functioning normally after this breaker reset. It's important to know that this isn't an instant fix and may take up to an hour to get back up and running as normal again.

What would make an AC not turn on?

These include: 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.

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.

Why wont my AC kick back on?

Resetting your thermostat is often all that's necessary to get it working again. A tripped circuit breaker is another common reason why your AC won't turn on. Using too many appliances at once can trip the circuit breaker. This is also common when there are power surges after a big storm.

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.

Why did my AC stop working all of a sudden?

There are a few reasons why this might happen. Some of the simpler causes may be that a vent is closed, or that the thermostat needs fixing. Some more major causes may be that the unit is low on refrigerant, signaling a leak, or that there is a problem with the fan.

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.

Why is my thermostat on but AC not turning on?

Why is my AC not turning on, but the thermostat is on? Your AC may not be turning on because of a dirty air filter. Regular cleaning and replacing the air filter is essential to ensure the proper functioning of the AC.

Why is my AC unresponsive?

Some of the most common reasons a central air system stops working include: coolant has run too low, the air filters are blocked or dirty, the coils are frozen over, or there is an electrical issue. To help you troubleshoot what exactly is wrong with your central AC, we've detailed the most common issues below.

How do I turn AC on?

You go to your thermostat and switch on the AC. We recommend running the AC in fan mode first to allow dust to clear from the system. After 10 minutes, switch from fan mode to cool. Once turned on, check that cold air is coming from the vents.

How do I reset my AC fuse?

How to Reset Air Conditioner Breaker in Six Steps
  1. Step 1: Find the Service Panel or Circuit Breaker Box. ...
  2. Step 2: Power Down the AC Unit and Thermostat. ...
  3. Step 3: Find the AC Breaker Switch and Reset It. ...
  4. Step 4: Try the Isolator Switch. ...
  5. Step 5: Use the Reset Button on the AC Unit.

Why isn't my AC compressor turning on?

You'll want to have the unit examined for signs of a blown fuse, tripped circuit breaker, broken thermostat, or dirty air filters. Dirty or clogged filters commonly make AC compressors stop working. When it comes to operating your cooling system properly, be realistic with the temperature setting on your thermostat.

Why is there no power going to my thermostat?

In this case, you'll want to check for the following: Tripped Circuit Breaker: The main issue here is not with the thermostat itself but with the electrical panel. Go to the breaker panel and locate the circuit breaker for your thermostat. If it's off, try to reset the breaker switch.

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

Press the reset button. Most models require you to hold the button down for 3-5 seconds before releasing. Restore power to your AC. Restore power to the unit at the circuit breaker, and make sure the unit is set to “on” and your thermostat is set to “cool.”

Why is my outside AC unit not working but inside is?

Over time, the fan motor on the outside AC unit can wear out, causing the outdoor unit to stop working even when the inside AC unit is on. The fan motor can last 10 to 20 years with proper maintenance, like annual inspections and regular AC unit cleanings, but it will wear down faster without regular maintenance.

Why is my AC not blowing when I turn it on?

If your air handler is running but not blowing air, there are two likely scenarios: either a broken AC blower belt or an issue with the motor itself. If the air handler is humming or buzzing but not making the mechanical sounds of a motor running, you're most likely talking about an issue with the motor itself.

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.

How do I know if my AC fuse is broken?

If you think your air conditioner has blown a fuse, the first sign you'll notice is that the outside AC unit is inoperable. The best way to check for a blown fuse is by using a voltmeter. Be warned — you are working with live electricity and should use extreme caution when troubleshooting your system.

Where is the AC reset button?

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.

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