AC Fan Not Spinning: Common Reasons and How to Fix Them

You might want to check it yourself to fix it fast and prevent things from getting worse. But do you know why your outdoor air conditioner fan stopped working?

If not, you’re in the right place. We’ll cover common causes and show you how to get it spinning again before calling air conditioning services for major issues. Let’s get started!

7 Signs Your AC Fan Might Have an Issue

Here are seven signs your AC fan isn’t spinning, so you can tell if there’s really a problem:

1. No Sound from the Fan Grille

You’ll hear two main sounds from your outdoor AC unit: the low compressor hum and the loud ‘whooshing’ of the fan. Usually, the fan noise is the loudest from afar.

If you’re close and only hear the compressor’s hum with no sound from the top grille, then your AC fan isn’t spinning.

2. No Movement from the Blade

This is the clearest sign the AC fan is not spinning. But, you need to get close to see through the safety grille.

If the unit’s on, the compressor vibrates, but the fan blades don’t move, there’s a problem. A slow-spinning fan appears blurry, while a stopped one shows the blades’ shape and dust clearly.

3. Clicking Sounds Without Wind Noise

When your AC turns on, you’ll hear a “clunk” and then the fan starts. If you hear the “click” and “clack” but only a quiet hum with no air, it means the electricity is working, but the AC fan is not spinning.

The “click” shows the system wants to run, but silence means the fan motor isn’t working. This causes your AC isn’t blowing cold air.

4. Compressor Short-Cycling

Compressor short-cycling occurs when the AC compressor repeatedly turns on and off. If the condenser fan isn’t spinning, the refrigerant can’t release heat and overheats.

The high-pressure switch trips to shut off the compressor for safety, and when pressure drops, the system tries to restart but quickly overheats and trips again.

5. Extreme Heat Radiation from the Outdoor Unit

Do you notice your outdoor unit is very hot? That could mean your AC fan is not working.

When the condenser fan stops spinning, it can’t pull cool air through the fins to remove heat. As a result, heat gets trapped inside, making the metal case and surrounding air feel really hot.

6. Warm Air from Indoor Vents

You know how the AC system works, right? It moves heat from inside your home to the outside. And if the AC unit fan stops, it ruins the whole process.

The indoor blower runs, but the air isn’t cooled well because the outside “heat dump” isn’t working.

7. Burning Smell

If you smell a strong burning odour near your unit, your fan motor is likely stuck or jammed but still drawing power. It heats quickly, and the smell comes from varnish melting on the copper windings.

Overheating can also burn nearby wiring and plastic, causing a melted plastic smell around your outdoor unit or vents.

8 Common Causes of AC Fan Not Spinning and How to Fix Them

You already know the signs that your AC fan might have a problem, but you might be wondering, “Why isn’t my AC fan moving?” Here are some common causes and how to fix them:

1. Debris Obstruction

You might not realise it, but something nearby could be blocking your outdoor AC unit. Even small objects can get caught in the condenser fan.

Why? Because your outdoor unit acts like a vacuum. It can suck in loose things like twigs, gum nuts, or even a gecko nest, which can get stuck between the fan blade and the grille.

If the object’s resistance is stronger than the motor’s power, the blade gets stuck, but the motor keeps running, trying to push through.

How to Fix It

1. Turn off the AC at the isolator switch to prevent it from starting during repairs.
2. Check the grille for any debris obstruction touching the fan blades.
3. Use a long, non-conductive tool like a wooden stick or plastic rod to clear the obstruction.
4. Gently push the blade with the tool to see if it spins freely.

2. Ice Blockage

Sometimes, it’s the indoor AC fan which stops working. And it’s usually because of ice buildup.

When airflow gets blocked, usually because of a dirty AC filter, the evaporator coil gets way too cold. Without enough warm air moving over it to warm things up, the moisture in the air freezes onto the coil’s surface.

Over time, layers of ice build up and turn into a thick chunk. This is when your air conditioner fan isn’t working properly.

So, how to fix ice blockage that makes your AC fan not spin at all?

1. Switch your AC to “Fan Only” mode to melt the ice.
2. Check if the indoor filter is dirty, that could be why it froze up.
3. Look for water melting around the unit which confirms the defrosting is working.
4. If the filter is clean and it’s still frozen, call a professional. It’s probably a refrigerant leak that needs fixing, or cleaning the AC coils could be the solution.

3. Motor Thermal Overload

Every fan motor has a safety feature called a thermal overload switch. In Australia’s harsh climate, your fan motor already struggles to shed heat.

If it gets too hot, the thermal overload switch trips, cutting the power to prevent a fire. The fan stops to cool down. The rest of the AC may keep running until the entire system shuts down from overheating.

Here’s how to check and fix it:

1. Turn the system off and give it a break.
2. Wait 30–60 minutes so the motor can cool down naturally.
3. While you’re waiting, gently hose down the outdoor unit fins to clear out dust which causes the heat.
4. Turn it back on. If it runs for 20 minutes and stops again, the motor is failing and needs replacement.

4. Loose Fan Hub

The electric fan motor and plastic blade are separate AC unit parts connected by a fan hub. It’s held in place by a small metal grub screw.

Over years of outdoor vibration, the screw can loosen. This causes the motor shaft to spin freely inside the plastic blade’s hole. As a result, the fan either stops moving or spins too slowly due to loss of grip.

How to deal with this issue that makes your AC fan not spinning?

1. Turn off the power first.
2. Push the blade back and forth. If it wobbles or feels loose from the motor shaft while the shaft stays still, that’s the issue.
3. Fixing this means removing the fan grille and using an Allen key. So, you need to call a technician for this.

5. Seized Motor Bearings

This mechanical problem inside the fan motor happens when the bearings dry out or get rusty. That makes the shaft stick and stop spinning.

The increased friction makes it tough for the motor to turn. You might hear a humming noise when it’s on, but the fan won’t move.

Here’s how to fix the AC fan not spinning due to seized motor bearings:

1. Turn off power at the isolator switch.
2. Push the fan blade with a long, non-conductive tool.
3. Check if it spins easily. If it feels stiff, the bearings are seized.
4. Call a qualified technician to replace it.

6. Failed Capacitor

What makes your fan start? It’s the run AC capacitor, a small cylinder that stores and supplies electrical energy to kickstart and keep the motor spinning.

When it malfunctions, the motor may hum but lack enough power to turn the blades, so they stay still.

Here’s how to fix this issue:

1. Turn off the power at the outdoor isolator switch.
2. Shine a flashlight through the grille to locate the silver cylinder. If the top appears swollen like a soda can, it has failed.
3. Call an HVAC professional to replace it, as it involves high-voltage electricity and shouldn’t be DIY.

7. Faulty Fan Relay

The Control Board sends signals to the compressor and fan. Sometimes, a gecko, ant, or power surge damages only the relay controlling the fan.

That causes the board to forget to turn the fan on. So the fan stays off while the compressor runs, overheats, and trips off.

Here’s how to check and fix it:

1. Turn off main power for 5 minutes to reset the board’s logic.
2. Turn it on. If the compressor starts but the fan doesn’t, and it spins freely with a stick, the signal is missing.
3. To identify a bad relay, check voltage on the live board. Usually, the board needs replacing.

8. Burnt-Out Fan Motor

It’s not just seized bearings that can prevent your AC fan from spinning. A complete burn-out motor can also be the cause.

The condenser fan motor has the toughest job in your outdoor unit. Over time, it can fail due to overheating, electrical problems, or prolonged use.

What to do if you think your fan motor is burnt out:

1. Turn off the unit and check if the fan motor smells like burning plastic.
2. Carefully touch the top of the unit. If the motor housing feels hot after turning off, it likely overheated.
3. Stop and call a professional to test the windings with a multimeter and replace the motor if necessary.

How to Make Your AC Fan Last Longer?

Here are tips to extend your AC fan’s lifespan and avoid unnecessary repairs or replacements:

• Clear the grille every month. Leaves and debris block the intake. This causes turbulence and pressure drops that lower efficiency. Regular brushing keeps airflow clear and protects the motor.
• Clean indoor filters regularly to prevent clogs that block airflow. Blocked filters make the blower motor work harder, risking overheating. Washing the filter restores airflow and cools the motor.
• Keep plants at least 1 metre from your outdoor unit. Do this every three months. Debris falls from nearby plants, and vines or bushes touching the unit give ants and geckos easy access to the electrical box.
• Wash the fan blades every year. Turn off the AC and clean the blades to prevent mud or dirt from sticking to one side. If it does, the fan becomes unbalanced. This causes the motor shaft to vibrate and break the bearings.
• Tighten the grille screws annually. A loose screw can cause the metal to hit the spinning fan blade, shattering it and bending the motor shaft. It’s a quick 2-minute fix that can save you $500 in repairs.
• Check your fan blades yearly. Tiny cracks near the centre can appear before they break. So replace them early to avoid damage to the motor and casing.
• Apply anti-corrosion spray like Lanolin. Rust at the motor shaft makes it swell and stick, so sealing it prevents damage and avoids motor replacement.

FAQ about Non-Spinning AC Fan

Here are some common questions about your AC fan stopping:

Should I turn off my AC if the fan isn’t spinning?

Yes, do it right away. A compressor running without a fan can’t cool itself and will overheat quickly. That can cause serious damage or burn out the motor. Turn off the system at the thermostat or circuit breaker.

Why is my AC humming but the fan is not spinning?

The “hum” is likely your compressor running or the fan motor trying to start but failing. Usually, it’s a bad capacitor (not enough power) or something stuck. The motor gets power but can’t turn the blades.

Can I run my AC if the fan is not working?

No. The indoor blower moves air, but the outdoor unit can’t release heat. It will blow warm air for a few minutes before the compressor overheats and trips the safety switch. This can permanently damage the compressor.

Conclusion

Now you know what to look for when your AC fan won’t spin. Whether it’s a simple ice blockage or a relay issue, spotting these signs keeps you in control.

Also, catching problems like a short-cycling compressor early can save you big repair costs. But keep in mind that you can’t handle all problems yourself.

So, if it’s complicated, call a professional. At Lightning Bult, we’re ready to help you diagnose and fix the issue safely and effectively.