Why is my AC unit running inside but not outside?

Author: Mrs. Marquise Johnson III  |  Last update: Monday, January 19, 2026

If your inside unit is running but the outside AC unit fan isn't running, there could be a few potential causes. To diagnose the problem, first, check the circuit breaker, then inspect the condensing unit for any visible damage, and then check if the fan's airflow is blocked.

Why is my AC running in my house but not outside?

When the outside unit breaks down but the inside unit is running, the culprit may well be a broken compressor in the outside unit. That's typically a major repair, something that might even warrant a system replacement.

Why is my AC unit not turning on outside?

If your outside AC unit is not turning on, one of the most common (and simplest) reasons is an electrical issue like a tripped circuit breaker cutting the power to the unit. Other potential reasons with simple fixes include the thermostat being set incorrectly and the unit being low on refrigerant.

Why is the fan on my outside AC unit not running?

In short, common issues that can cause an air conditioning unit fan to stop spinning are electrical issues, problems with the capacitor, contactor issues, a burnt out air conditioner motor, a broken fan belt, or clogged air filter.

How to reset the AC unit outside?

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.

A/C Condensing Unit Runs Constantly T-stat is OFF

Why is the outside of my AC not working?

Make sure the outside unit is turned on (there's probably a switch near the unit). If the outside unit has a separate circuit breaker, check your circuit box and make sure it hasn't been tripped. A more serious issue if the outside air conditioning unit's not working is a broken compressor, capacitor or fan.

Can the AC run without the outside unit running?

A central AC system consists of indoor and outdoor units. An indoor air handler can continue running when the outside unit has shut down. While air will blow from the vents, it won't be cooled; it may be as warm as the summer air outside.

Should the outside fan be running when AC is on?

Does The AC Fan Outside Always Run? The answer to this is no. The AC fan does not run non-stop. It's intended to cycle on and off, depending on the needs of the HVAC unit.

Why is my AC condenser not kicking on?

A condenser that won't come on could have a variety of problems, because there are many issues that would prevent activation. The wiring might be wrong, a motor might be faulty, the compressor could have gone bad, or it is completely out of refrigerant. Might even be a problem with the thermostat.

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.

How do I get my outside AC unit to kick on?

Outside AC Unit Won't Turn On? What to Do Before Calling for Repairs
  1. Make sure the thermostat is set to COOL. ...
  2. Check the emergency or shut-off switch. ...
  3. Check the inside unit's power switch. ...
  4. Look for a blown fuse or tripped circuit breaker. ...
  5. Look for problems with your condensate drain line. ...
  6. Try resetting the air conditioner.

How do I know if my outside AC fuse is blown?

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.

How to know 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.

Why does my AC unit come on inside but not outside?

If your inside unit is running but the outside AC unit fan isn't running, there could be a few potential causes. To diagnose the problem, first, check the circuit breaker, then inspect the condensing unit for any visible damage, and then check if the fan's airflow is blocked.

How do I reset my AC thermostat?

Here are the steps you need to take to reset your AC thermostat.
  1. Shut Down Your AC at the Thermostat. The first step in resetting your AC thermostat is to turn it off at the AC unit. ...
  2. Find Your Circuit Breaker Box. ...
  3. Reset the Circuit Breaker for Your AC Unit. ...
  4. Wait 30 Seconds. ...
  5. Turn the AC Thermostat Back On.

How much does it cost to replace a capacitor in an air conditioner?

For AC capacitor replacement, anticipate spending between $150 and $400, depending on the capacitor's type and accessibility. A bad AC capacitor is a fairly minor repair, and most HVAC technicians will recommend a repair rather than replacing the unit when the capacitor is the problem.

What are the symptoms of a clogged AC condenser?

4 Common Warning Signs that You Have a Bad AC Condenser
  • Your Air Conditioner is Not Cooling Your Home. ...
  • Your Air Conditioner is Making Strange Noises. ...
  • Your Air Conditioner is Not Turning On. ...
  • Your Air Conditioner is Leaking Refrigerant.

How do I reset my outside AC unit?

In AC systems, the air conditioner reset button is on the outside unit's lower edge, typically close to the ground. Some models have the reset button located behind the service panel, which may require tools to remove. Reset buttons are usually red or yellow with a clear “reset” label.

Why is my AC outdoor not working?

If your outside AC unit is not turning on, it could be a thermostat issue. If your thermostat clicks but the AC does not turn on, you could have an issue with the thermostat itself. Broken thermostats often fail to properly communicate with the rest of your heating and cooling system.

Why is my AC unit not kicking on the outside?

A tripped circuit breaker can be a major cause of why an outside AC unit isn't turning on. This occurs when the current is too high in the outdoor unit, causing the breaker in the fuse box or main electrical panel to switch off power to the unit, resulting in it not receiving any electricity.

Can AC work without outside fan?

Air conditioning without an outdoor unit is called water cooled air conditioning, because it uses mains water to cool down the internal refrigerant, rather than outside air. This allows the system to be fully internal, as all of its components are located within the property.

Does the thermostat control the outside unit?

The AC cooling process starts when the thermostat senses the air temperature needs to be lowered and sends signals to the central air conditioning system components both inside and outside the home to start running.

Should the outside fan run when AC is on?

The short answer: Definitely not. (Unless you have manually engaged your outside fan to run constantly, but it shouldn't be running for hours on it's own.) If your HVAC is functioning correctly, it should keep your house cool by cycling on for 15-20 minutes at a time—with distinct pauses in between each cycle.

How much does a compressor cost for an air conditioner?

On average, AC compressor costs range from $800 to $2,300, with most folks paying $1,200 for a new one. However, your price will vary depending on factors like the size and brand of your compressor. Before you schedule your replacement, read on to learn about all AC compressor cost factors.

How do I know if my outside AC unit is working?

Go outside and see if the condenser is turned on.

While the condenser is on, place your hand about a foot above it. There should be air blowing out of it. If there is no air, the condenser is not working. If the air feels cool it means that your air conditioner is not removing any heat from inside of the home.

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