Why did my AC suddenly turn off?

Author: Lisa Lubowitz  |  Last update: Sunday, November 9, 2025

AC Problems that Cause Your Unit to Shut Off Unit is overheating – This usually indicates that there is grime buildup within the compressor, but it could also be indicative of a more complex refrigerant leak. Faulty thermostat – The wiring may have been damaged on your thermostat, or there may be an electrical problem.

Why did my AC randomly turn off?

Several reasons could cause your air conditioner to keep shutting off, such as a dirty filter, low refrigerant, or a malfunctioning thermostat. To fix it, try cleaning or replacing the filter, ensuring proper refrigerant levels, and checking for thermostat issues.

Why did my AC suddenly stop running?

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.

What is the first thing to check when the AC goes out?

The first thing you'll want to do is check the thermostat. If you have air that's controlled by a thermostat, make sure a faulty thermostat isn't what's causing the problem. In some cases, the batteries may have died or the unit is malfunctioning. Reset the thermostat to see if that turns the AC unit back on.

Why did my AC just shut off and won't 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.

9 Reasons Why Your Air Conditioner Starts Then Stops Quickly

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.

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.

How do I know if my AC blew out?

In addition to a sudden stop, these signs of blown AC fuses require your attention:
  1. Strange sounds are coming from your air conditioning unit.
  2. Your circuit breaker keeps tripping.
  3. Your unit smells like it is burning or gives off the smell of exhaust.
  4. Water is leaking from the unit.

Why is AC not working suddenly?

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. Look for dirt clogging the condenser fins on the outside unit and clean the fins if necessary.

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

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

Why did my AC stop 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.

Where is the reset button on an AC 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 to tell if a thermostat is bad?

A bad thermostat can be detected when your AC or furnace is not turning on, your HVAC systems are not turning off, the thermostat not responding, your HVAC system is short-cycling, the room temperature not matching the temperature displayed on the thermostat, and the programmed setting resetting themselves.

What happens if AC is turned off?

If you leave your air conditioner off during the day, indoor temperatures will continually rise while you're gone. By the time you get back, temperatures will be so high that your air conditioner will consume more energy cooling down your home than it would if you left your system on all day.

How to unclog an AC drain?

To unclog an AC drain line, turn off the power to the unit. Locate the drain line and use a wet/dry vacuum to suck out the clog. Flush the line with water using a garden hose or cup of water. Check and clean the drain pan under the indoor unit.

Why did my AC turn off all of a sudden?

Electrical issues: Electrical wiring problems, such as a tripped circuit breaker or blown fuse, can cause the AC unit to turn off by itself. Low refrigerant levels: If the refrigerant levels are too low, the AC system may not be able to cool the air properly, causing it to turn off by itself.

How long do air conditioners last?

It's important to be aware of how long air conditioners last, so you don't get the unwelcome surprise of a broken air conditioner in the peak of the summer heat. In general, air conditioners that are properly maintained can last 15 to 20 years.

How can I get my AC to start working again?

Troubleshooting a Broken Air Conditioner
  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.

How do you know if your AC is about to go out?

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.

Is a broken AC considered an emergency?

If your AC unit refuses to turn on despite multiple attempts, it's crucial to consider it an emergency. A complete system failure could be due to electrical issues, motor failure, or a malfunctioning compressor.

Can an AC burn out?

A failed fan is a problem in general for an AC, since it won't allow the outdoor condenser coils to properly release heat. But the fan is also responsible for venting heat from the compressor, so if the fan stops running, the compressor's temperature will rise and lead to burning out.

Why is my AC unit not kicking on?

Check the thermostat

You should check if it's been set to the correct temperature and also make sure it's set to “cool”. If the AC settings are not right, it won't turn on. You can also check if the batteries in the thermostat are fresh and replace them if needed.

Will AC turn on if fuse is blown?

Fuses play a vital role in maintaining the overall integrity of the AC system, ensuring its safe and reliable operation while also safeguarding against potential fire hazards that could arise from electrical failures. If the AC fuse blows, your air conditioner won't turn on.

How much does it cost to replace fuse in AC?

A fuse replacement can cost between $75 and $300. These are similar to car fuses and can blow if they get overloaded. The good news is that this type of repair is quick and not likely to rack up excessive labor fees. A relay turns on an AC unit's outdoor condenser unit.

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