Outside AC Is Not Running But Inside Is: Causes, Troubleshooting & Fixes

Outside AC Is Not Running But Inside Is

The air conditioner should emit cool air to make the indoor atmosphere comfortable during summers. But sometimes strange things happen due to technical and cleanliness issues in the system.

Your unit is running and blowing hot air instead of cool air. Though there could be multiple reasons, start with checking compressor, fan, and outdoor unit.

If, after investigation, you assess that the outside unit of the AC is not functioning, but the inside unit of the air conditioner is working. 

There could be two explanations for the problem;

  • The outside unit hums, but the fan not working
  • The entire outside unit of the AC becomes dysfunctional

We will discuss both scenarios with solutions to ensure optimum AC performance for an excellent & comfortable indoor environment.

1. Fan Of The Outside Unit Is Not Working

Fan of the unit might be unable to spin because of any one or all of the following reasons.

Malfunction Capacitor

The capacitor helps in AC start-up. It uses stored power that runs fans in your air conditioner. It is an essential component of the unit that ensures AC running efficiently using the available energy.

Generally, it needs 6 to 7 times energy to start the motor, and once it gets velocity, operations need standard power.

So, if your machine is not working and the fan is not spinning, it’s probably a problem with the capacitor. There are two options either replace the existing AC capacitor with a new one or install a hard start kit.

Because of excess pressure during extreme heat and weather fluctuations, capacitors can go wrong.

You can start with a gentle push to the fan with a stick. If your push-starts the fan then you need to replace your capacitor as it might be on its end cycle.

If you leave a lousy capacitor working, it will have to function several times harder than leading to motor burning over a while. In addition, if the unit is a dual capacitor and attached to the compressor, it will further damage the system, and the compressor may overheat beyond maintenance.

Sometimes we ignore basic things that lead to problems in the air conditioner. If the fan is not working, there might be dust and debris around the fan’s axle. The motor bearings could get jammed or, the fan motor itself could be damaged.

Keep your machine clean and tidy. Make it a regular habit to restrict the accumulation of dirt and debris.

Insufficient Energy Supply

Not having enough power could be the reason for the fan not working. The fan of the outdoor unit needs a regular supply of energy. So, any interruptions to the fan assemble could stop the fan from spinning. There could be several reasons for this, and you should consult an HVAC specialist to diagnose and repair the power issue.

Problem with Contactor

The contactor runs the motor of the fan, if it malfunctions for any reason, the fan will stop spinning, and your unit will stop cooling. Taking a DIY method could bring several headaches and consumes a lot of time.

It will be better to hire a professional who knows all details about AC functioning and efficiently solve fan problems.

Damaged Fan Motor

Summers bring heavy pressure on the AC unit. The fan runs at high capacity and affects the motor adversely. It needs servicing and repairs at regular intervals.

If the unit does not maintain properly, the fan motor burns out and causes damage to the system. A damaged motor stops the fan from spinning or slows it down.

2. Entire Unit becomes Dysfunctional

Another scenario could be a dysfunctional entire outdoor unit. You can recognize this if the AC faces trouble switching on or making noises while in operation. If there is no air coming out from the vent, it means your AC needs a professional HVAC expert. 

Meanwhile, you can begin troubleshooting with the following steps.

Check Thermostat Settings

Start with checking the thermostat, whether on or not. The temperature setting should be at least three degrees below the temperature outside.

Reset the System

Check for accumulated dirt and debris that can also cause shut down. You can try the reset option, first switch off the air conditioner at the thermostat or the breaker. After that, wait for around one or two minutes, and switch on the HVAC unit.

Reset the machine could start the AC properly functional within ten minutes. If not, your unit needs immediate expert attention.

Circuit Breaker

The unit can also shut down because of circuit breaker tripping. There is a common problem with air conditioners when power consumption rises and load increases on circuit breakers. You can simply move it back to its place and resolve the problem. 

You can find tripped circuit breaker electric panel. Older houses and building place fuse box and if your property has a fuse box installed, you need to flip them ‘off’ then ‘on’ to re-start the system.

There are a couple of other components that you should check if you want to do it yourself, check the indoor switch, emergency switch, AC disconnect box, and condensate drain line.

Compressor Failure

The compressor is the heart of the air conditioner and ensures the optimum functioning of the system. It is a pump that regulates coolant under high-temperature conditions.

Your system can also shut down with something wrong with the compressor. Generally, if the compressor is not working, you need to replace it with a new one. And the replacement can cost way too much.


Air conditioner involves several technical and mechanical components. It is advisable to consult a registered and trustworthy AC technician to diagnose and troubleshoot problems.

They use the latest technology and tools with relevant knowledge to provide correct solutions. DIY methods might seem attractive, but if done wrong, it can lead to further damage, and you will end up paying more than you wished to save. Trust a professional for HVAC product maintenance always.

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