AC fan not spinning? Find the solution here

ac fan not spinning

An air conditioner is a critical part of any home’s HVAC system, particularly in areas that experience warm climates throughout the year. It keeps living spaces cool, improves air quality, and minimizes exposure to disease-causing allergens.

However, AC systems are prone to malfunction like any other equipment. Sometimes, they stop spinning, making it challenging to keep your home cool. Identifying the cause of the problem is the first step. The next part of the article highlights why your AC fan is not spinning and the possible remedies.

Issues with the Capacitor

The capacitor is one of the most critical components of an AC system. It stabilizes the system’s voltage and kickstarts the spinning process. AC systems have three motors (the outdoor fan motor, blower motor, and compressor motor), and each has an individual capacitor to start and keep it running.

Signs of a Bad Capacitor

Bad capacitors are the most common reason for AC fan not working. The problem occurs when the compressor motor doesn’t start correctly, stutters when turned on, and shuts off after a short while. Other signs of bad capacitors are:

  • The AC produces a humming sound
  • The AC failing to blow cold air
  • The AC shutting off alone

If only one capacitor has failed, the others may continue working, but the motor produces a noisy sound and doesn’t run for long. If the problem isn’t addressed immediately, the motor may start growing hot and eventually burn out. It’s best to turn the AC off as soon as you discover the humming sound.


Since it’s not easy to identify problems in an AC’s capacitor, it’s best to enlist the help of a technician. They will examine the system to find out if there’s visible damage and perform electrical tests.

ac not spinning

Power Issues

Electrical problems may also cause an ac fan to stop working after a while.

Signs of Power Problems

Power issues may be caused by many factors, including:

Damaged electrical wires: Electrical wires wear out and get damaged after some time, causing disconnection or shorting, which can cause the ac not to spin

Tripped breaker: A central cooling system’s outdoor and indoor components are powered by individual circuit breakers, and some can trip during power surges. Since each portion has its breaker, it’s possible for one breaker to trip and the other not to. If the breaker for the air conditioner outside unit fan is not working and trips and the indoor unit works, the AC system won’t emit cold air or stop spinning altogether. The indoor unit only facilitates air circulation, while the outdoor AC unit plays a critical role in cooling


A simple remedy is to check the electrical panel to determine if there’s a tripped circuit breaker and switch it back on. However, if it trips again, consider enlisting the help of an AC technician.

ac power not working

Broken Fan Blades

This is a common problem in older AC units as modern ones don’t use fan belts. Running the AC with bad blades wears out the motor, compelling you to perform more costly repairs.

Signs of Broken/Faulty Fan Blades

Outdoor AC units are notorious for developing bent blades because they’re exposed to damage from sticks, rocks, and other debris. Signs of a bent blade include:

  • Noise: The bends cause blades to strike the edge of the fan casing, creating noise.
  • Cracks: The bends may cause blades to crack too. If the crack is large enough, part of the blade drags against other parts when the fan is spinning. It’s easy to spot cracked blades because you can see through the top of the fan.


The best way to solve the problem is to replace the unit with a new one but if you’re not ready to do this, ask a technician to repair the belt.

ac fan blades broken

Burnt-out Motor

The motor is the most crucial part of an air conditioner system. It turns the blades allowing the AC unit to emit cool air. The motor is located within the condensing unit of the AC, which also consists of the condenser coil and the compressor.

AC motors are designed to operate at specific temperatures; usually, 70-150 F. Beyond this range, an ac fan motor is hot and not spinning. A burnt-out motor is a result of factors like:

  • Installing an over/undersized motor: It’s essential to check the manufacturer’s recommendations to ensure the right size motor is used.
  • Poor flow of air: If the fan blades have been installed incorrectly, the airflow might be poor, causing the motor to overheat.
  • A worn-out motor: AC motors wear out after prolonged use. If not replaced, it may overheat.
  • Overamping: It may be a result of an incorrectly sized fan blade or the wrong capacitor being installed.
  • Poor maintenance: If the motor is not kept clean and lubricated, it can overheat and burn.
  • Refrigerant leaks: Refrigerant lines are bound to develop cracks causing the refrigerant to leak. Refrigerant is a coolant, but it doesn’t need to be added regularly as in cars. However, leaks drain the liquid, which can put a strain on the system and cause it to run harder and overheat.
  • Dirty condenser coil: The component gets coated with dirt reducing its ability to release heat as it should. This can cause the motor to overheat and burn out.

Signs of a Burnt AC Motor

It’s essential to identify the signs of a burnt AC motor and address them early. They include:

  • Air conditioning fan won’t turn on
  • Fan blades rotate slowly or not moving
  • Rattling noise from the condenser when the AC is turned on
  • Humming or buzzing noises from the fan blades
  • AC runs intermittently
  • No cold air is produced
  • Fan keeps running after shutting off the AC

Solution: How to Fix an Air Conditioner Fan Motor

Regular maintenance prevents an AC motor from overheating and burning out. It may involve simple tasks like:

  • Vacuuming around the furnace
  • Cleaning the blower fan
  • Regular lubrication (usually once a year)
  • Ensuring the area around the air intake vent is clean
  • Scheduling regular maintenance with an HVAC technician
fix an air conditioner fan motor

Blocked Air Filter

Another reason an AC fan won’t spin is due to clogged air filters. Air filters keep the air quality crisp by removing pollen, dirt, and dust. Failure to clean the filters allows dirt buildup causing the air conditioner to use more energy to cool a space. The air quality is also compromised.

Signs of a Blocked Air Filter

Clogged air filters can cause AC to develop various problems. Most of them develop short cycling a problem that causes the AC to turn on and off every few minutes. When in top shape, the unit cycles on and off throughout the day. Blocked air filters worsen the problem as they become more frequent.

Clogged air filters also cause allergen buildup. With the air filters not filtering the air, allergens collect in the duct system. This means any time the fan is turned on; the allergens are released into the air. They may also cause freezing incidences due to restricted movement of the cold air. Consequently, the cold air causes ice buildup on the coils of the system.


The best way to prevent air filters from getting blocked is to clean them regularly (after 1-3 months). However, if your AC unit uses disposable filters, it’s best to replace them.

Faulty Belt

Older AC units use belts that wear out after prolonged use, which can cause the air conditioner fan not running. Most of the time, old AC belts get frayed and need to be replaced.

Signs of a Faulty Belt

A faulty belt causes the AC system to develop strange noises. The system may also squeal when turned on or cool the air unevenly.


The best way to deal with a faulty belt is to replace it with a new one. Alternatively, ask an HVAC technician to help you replace the old AC with a modern system.

ac fan solutions

Issues with the Contactor

The contactor is the part that regulates the flow of electricity throughout the AC unit. It conducts and restricts electrical currents allowing the AC unit to operate. Contactors wear out after prolonged use or when the system overheats, inhibiting the electrical flow to the system.

Any adjacent AC components hardly receive electricity causing ac fan not turning on. Contactors may also get stuck in the up and down position. Those in the ‘up’ position cause electricity to get blocked between components which is the primary reason for the AC not spinning.

The ‘down’ position, on the other hand, causes electricity to continue flowing to the components even after cooling stops.


Regular AC maintenance goes a long way in ensuring contractors function properly. During maintenance, the technicians inspect and remove accumulated dirt on the contactors to prevent future problems. If they still develop problems, it’s best to replace them.

Now you know why the ac fan is not spinning. Be sure to identify and address any of these issues immediately; otherwise, the AC may develop more problems that need costly repairs. It’s best to engage HVAC professionals as they are knowledgeable and have the essential tools required for repairs.