Why Is My AC Compressor Not Turning On?

Alexis Labadie Profile image

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Updated May 18, 2023

If you feel like your AC system isn’t working well, you may ask, “Why is my AC compressor not working?” Like many other issues with the best air conditioner, you may experience various complications with your compressor. When your compressor malfunctions or dies, it’s disastrous to your entire system since professionals widely consider the compressor at the beginning of the air conditioning cycle. There are numerous reasons this can happen, from a lack of power to dirty coils or faulty wiring. Keep reading to learn more.


  • An AC compressor may become faulty due to overheating or other complications.
  • Check the power to your AC before calling a maintenance specialist about possibly replacing your compressor.
  • Do not try to repair or replace your compressor unless you are certified to do so.

Why Air Conditioner Compressors Stop Working

Problems such as power issues, faulty wiring, and much more can be the culprit. This compressor in your outdoor unit compresses the cool gaseous refrigerant and increases its heat and pressure before entering the condenser. As a result, the entire system may not work when you have a faulty compressor. Although, if the AC is not working in one room, that’s not a problem with the compressor.

On the other hand, if you’re stuck with an AC fan not spinning, it might be another issue altogether.

Insider Tip

Regular maintenance can help you avoid some ‌causes of faulty or dead compressors.

These problems require a specific solution, but you can avoid most of them with regular maintenance and cleaning. However, you may need to call a service specialist if you find you cannot fix the issue, like if you need an ​​air conditioner circuit board replacement.

Lack of Power

One common issue that causes your compressor to stop working is a lack of power. Of course, you can quickly determine whether you’ve lost power in the case of an outage since everything stops working. However, you likely won’t notice immediately if your AC alone loses power. In fact, the average AC compressor lifespan is 10-15 years, depending on the conditions and how frequently it’s used.

Power fluctuations cause surges to affect your air conditioning unit. As a result, the inside capacitors may become damaged and no longer store power for AC start-up or running. Additionally, you may have a tripped breaker or blown a fuse for your AC unit.

When you have an outage in your area, pay attention to how your air conditioning system acts once power is restored. A capacitor problem may need to be repaired by a certified technician. If you have blown a fuse, one or more of your fuses in the fuse box will appear different. A tripped circuit will show the switch facing the opposite direction.

Other Possible Causes

  • Dirty condenser coils
  • Low refrigerant charge or too much refrigerant
  • Incorrect suction line size
  • Faulty wiring
  • Contaminants
  • Insufficient oil lubricant

Prevention of Compressor Issues

A regular maintenance program can help prevent some air conditioning compressor problems and keep your energy efficiency up. Wash your condenser coils at regular intervals. Dirty coils can lead to the compressor’s continuous overheating, causing the compressor to malfunction over time. You should also clean your vents and each dirty air filter. If you haven’t replaced your filters in a while, consider installing new ones. Because if you don’t, there’s a good chance your A/C will stink when you turn it on.

If you hear a humming sound coming from your high-end 15000 BTU AC unit, ‌check and replace capacitors and starter relays. As I mentioned above, occasionally ‌check for blown fuses or tripped circuit breakers, especially after power outages. Additionally, you may want to have service performed before the summer.

STAT: If it’s less than 50 percent of the cost of buying a whole new unit, it’s probably the best way to go. (source)

A compressor problem can be determined by ruling out other problems that can cause similar issues to those described above. This also includes refreshing the AC compressor oil. If you have considered each air conditioner component and found no other cause, you may have a faulty or dead compressor. Check out our page on how to fix an AC compressor if you are curious about fixing it yourself.

However, these elements cannot be replaced by anyone except a certified technician. Unfortunately, compressor replacement is a costly repair, so air conditioner maintenance is crucial. Sometimes, when the compressor and air conditioner are old, or there are other complications, it may be worthwhile to replace your entire unit.


How do I know if my AC compressor problem is serious?

If you experience problems with noise levels, weak or warm airflow, or tripped breakers, your issue may be serious.

What is an AC Compressor?

An AC compressor starts the cycle by taking refrigerant and turning it into a gas. It then passes this gas to the condenser, where it is turned back into a liquid, which cools the air.

What are the symptoms of a weak AC compressor?

Some signs of a faulty or weak AC compressor include blowing warm air, frequently tripping the circuit breaker, shaking when the system starts, and strange noises.

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