Why Is My Outside AC Unit Not Running But Inside Is?

image of an AC compressor unit that is not working

The rising temperatures signal that summer is here. Most places are so hot that air conditioners are an absolute necessity. By now, some homeowners may have found that their air conditioner may display issues and not work as expected. For example, the outside AC unit not running but inside is. This is a common problem that has several possible reasons. This article explains all you need to know and what you can do about it.

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Why Is My Outside AC Unit Not Running But Inside Is?

air conditioner condenser fan close up

The indoor and outdoor HVAC units work together to reach the desired temperature in your home. If one isn’t working, the house cannot cool no matter how much time passes. There are two methods you can do find out if the outside unit is running or not:

  • See if the condenser is making any sounds. Some units were designed to have quiet operations, but you should still hear a low hum. If there is a complete absence of sound, the compressors and motors aren’t functioning as they should.
  • Check if the indoor air handler releases warm air. Place your hand against the indoor air conditioning unit. If it is blowing hot air instead of cold air, the outdoor unit isn’t working correctly. The warm air only passes through the air conditioning system instead of going through the cooling cycle.
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What Causes The Outdoor Air Conditioner Fan To Stop Working?

The problem can usually be attributed to fan failure. The blades may not be moving, but the other components may work fine. This can happen even if you regularly replace the air filters and do other upkeep tasks. Here are several common reasons that fan stops rotating:

Deficient Power Supply To The Air Conditioner

Fan motors are electricity-powered. If they do not receive adequate power, they won’t run properly. It can be hard to determine what is stopping them from working in different cases. An experienced air conditioner technician can assist you in making the right diagnosis and repair.

Air Conditioner Contactor Problems

multimeter and run capacitors of an outdoor air conditioning unit

The contactor controls the fan motor. Therefore, if this component fails, the blade will stop spinning. Never try to fix this on your own because the problem might get worse when left in a novice’s hands. Have an expert look at it right away to receive a reliable solution.

Burnt Out Air Conditioner Fan Motor

Excess stress can lead to motor burnout. Motors also eventually succumb to wear and tear, and poor maintenance only hastens their deterioration. Regular maintenance is crucial, so problems are resolved at their earliest stages. This also means you avoid costly repairs down the line.

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Bad Air Conditioner Capacitors

Bad capacitors can cause outside fan failures. These parts store energy to ensure the blades always spin. This is similar to batteries that lose their energy storage abilities after heavy use. Capacitors can also incur damages from high temperatures and power surges. A failing capacitor cannot power the fan.

You can use a long wooden stick to check if this is the problem or not. Slide it through the fan grate and gently nudge the blades to see if this helps them start spinning. If it does, you likely have a bad capacitor. After some time, the fan won’t rotate even if you kickstart it. Professionals should handle all replacements, including dealing with high voltage and sensitive electrical parts.

Debris On The Axle

External force, like when you use the stick, should be sufficient to make the blades rotate. If you have problems with this, check if there is debris in the fan axle. There might be dirt accumulations in the motor’s bearings as well. Hire a technician to disassemble and clean all parts to ensure continuous movement.

What If The Whole Outside Air Conditioning Unit Isn’t Working?

Sometimes, the fan isn’t the only component that stops working. It could be that the entire outside unit has stopped working. This is troublesome for homeowners, and it may need professional help. No homeowner wants to have a non-operational air conditioner in the middle of the summer. Therefore, take action as soon as possible to resolve the issue. Here are the likely causes of the sudden system failure:

Air Conditioner Thermostat Settings

image of hand adjusting thermostat due to air conditioner outside unit not working

Check the basics before jumping to conclusions. Ensure that the system setup is correct. Start with the thermostat. A family member might have pushed the wrong buttons, setting the temperature too high. See if lowering the temperature settings makes any difference. You might even notice that the thermostat isn’t switched on. Replace the old batteries to get the thermostat to work again.

Dirty Outside Compressor Unit

A dirty outdoor unit can lead to overheating compressors. When it is too dirty, the heat cannot escape outside. When the system cannot tolerate the heat anymore, it will shut down. Check the outdoor unit for dirt and debris. Switch off and disconnect the unit before you start cleaning. You can also opt to have a qualified HVAC professional help you clean it.

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Safety Switch Lock

Cooling systems are equipped with safety switches. This component locks the outdoor unit when they sense danger. A reset is needed to switch it on again. Turn the system off via the thermostat or breaker. Turn it on after a minute or so and check if it’s working normally again. If it isn’t, call a professional to conduct further inspections and repairs.

Tripped Air Conditioner Circuit Breaker

circuit breaker box

A recent thunderstorm might have overloaded your circuit breakers because of the power surges. See if any of the breakers tripped in your circuit panel. Turn them off and on again. You might have a fuse box if you live in an older home. One or more fuses may have blown, so they need to be replaced. Call an HVAC technician to replace the fuse at the shut-off box if that’s what your air conditioner has. There are situations wherein the breakers constantly trip despite trying to normalize their state. A licensed electrician is needed to resolve the deeper electrical problem if this is the case.

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Air Conditioner Compressor Failure

The most crucial air conditioner component is the compressor. It pumps the refrigerant throughout the system at the correct level of pressure. A faulty compressor means the air conditioner cannot cool the indoor air. A sign that it is failing is when you hear a loud noise, or it stutters when you switch on the air conditioner. It won’t turn on completely as time passes. Repairing the compressor can be expensive. Sometimes, you may need to upgrade the system completely.



It can be confusing when the outdoor unit doesn’t run when the indoor unit does. A quick check can help determine the likely cause. You might even be able to bring it back to normal functionality with minimal effort. However, the problem could also be more complicated in some cases. If so, call an HVAC professional to assess, diagnose, and resolve the issue. They can find the culprit and do the repairs so your air conditioner runs as it should again. Also, be sure to schedule central air conditioner maintenance on an annual basis. This helps a slew of cooling system problems from occurring in the first place. Also, it promotes energy-efficient performance, improved comfort, while reducing your home cooling costs.

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Call R.F. Ohl For All Of Your HVAC Requirements

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When you need exceptional heating and cooling services in the Poconos and the Lehigh Valley, Pennsylvania, look no further than R.F. Ohl. We have highly trained and the best professionally certified technicians who can provide you with top-notch HVAC installations, replacements, repairs, and maintenance. Each of our friendly techs is skilled, experienced, and knowledgeable in servicing your HVAC system correctly.

R.F. Ohl guarantees highly competitive HVAC service prices in the locality. Rest assured, our tune-up services can improve your home’s indoor air quality and comfort, and increase energy efficiency while lowering your energy bills. If you need an HVAC repair or replacement system, we can recommend the best and most budget-friendly solutions for your home. All of our work comes with a guarantee to ensure your satisfaction. Call R.F. Ohl today and schedule a service appointment. We offer free, in-home estimates.

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