Why is my AC running but not blowing air?

Picture this: It’s a scorching summer day, and you’re seeking refuge in the cool comfort of your home. You hear your air conditioner humming, signaling it’s hard at work. But something’s off—the cool breeze you expect isn’t coming through the vents. If your AC is running but not blowing air, you’re not alone. This common issue can be frustrating, but the good news is that there are several DIY solutions you can try before calling in the pros.

Important notice

The information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for all kinds of DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes, part replacements, etc. For the most accurate guidance, we strongly recommend consulting the manufacturer documentation for your specific appliance model or contact us with any questions.

Common reasons your AC isn’t blowing air

Blocked or closed vents

Sometimes, the simplest solution is the most overlooked. Blocked or accidentally closed vents can restrict airflow in certain areas of your home.

Steps to open and unblock vents

• Walk through your home and locate all the AC vents.
• Make sure each vent is open. Adjust the vent louvers if necessary.
• Remove any obstructions like furniture, curtains, or rugs that may be covering the vents.
• Clean the vent grilles with a vacuum or duster to remove accumulated dust.

Thermostat issues

Your thermostat communicates with your AC unit to regulate temperature. If it’s malfunctioning, the unit may run without blowing air.

Checking your thermostat

• Verify the thermostat is set to the correct mode (cooling) and temperature.
• Replace the batteries if it’s a battery-powered model.
• Clean the thermostat to remove dust that may interfere with sensors.
• If you suspect a wiring issue, consult the manufacturer’s manual for troubleshooting steps or consider professional assistance.

Clogged air filter

The air filter is key to maintaining the airflow and air quality in your home. Over time, the filter can become clogged with dust, pollen, and other debris, restricting the airflow.

How to check and replace your air filter

1. Turn off your AC unit for safety.
2. Locate the air filter panel. This is often found near the return air duct or the air handler.
3. Open the panel and remove the filter. Take note of the filter’s size and orientation.
4. Inspect the filter. If it appears dirty or clogged, it’s time for a replacement.
5. Insert a new filter, making sure it’s facing the correct direction (look for the airflow arrow).
6. Close the panel and turn the AC unit back on.

Regularly replacing your air filter can not only restore airflow but also improve your home’s air quality. For more tips on maintaining clean air, check out our guide on how to get better air quality from your window air conditioner.

Dirty condenser unit

The condenser unit, located outside, releases the heat absorbed from inside your home. If it’s dirty or blocked, it can affect the entire system’s performance.

Cleaning the condenser unit

1. Turn off the AC unit’s power at the main breaker for safety.
2. Remove any debris or vegetation around the unit to allow proper airflow.
3. Use a garden hose to gently rinse the condenser coils from the outside in. Avoid spraying directly into electrical components.
4. Avoid using high pressure, which can damage the fins. A gentle stream is sufficient.
5. Allow the unit to dry completely before restoring power.

Frozen evaporator coils

Evaporator coils absorb heat from your home. If they become covered in ice, it can block airflow.

How to defrost evaporator coils

1. Turn off your AC unit to stop it from running and prevent damage.
2. Open the access panel to the evaporator coils, typically located inside the air handler.
3. Allow the ice to melt naturally. This may take several hours. Do not attempt to remove the ice manually, as it could damage the coils.
4. Once thawed, check for underlying issues, such as dirty coils or restricted airflow.
5. Gently clean the coils with a soft brush or coil cleaner to remove dust and debris.
6. Close the panel and turn the AC unit back on.

Prevent future freezing by regularly maintaining your unit. Learn more about how to clean your air conditioner the easy way.

Electrical problems

Electrical issues can prevent the blower motor or other components from functioning properly.

Warning: Live voltage testing can be dangerous and should only be performed by experienced individuals. Always exercise extreme caution to avoid electric shock.

Inspecting for electrical issues

1. Turn off the AC unit’s power at the main breaker for safety.
2. Examine the unit’s wiring for signs of damage, such as frayed wires or loose connections.
3. Check the circuit breakers and fuses associated with your AC unit. Reset any tripped breakers or replace blown fuses.
4. If comfortable and experienced with electrical systems, you can test for voltage:

• Set your multimeter to the appropriate AC voltage setting.
• Carefully place the multimeter probes on the terminals where you need to measure voltage, such as input terminals of the blower motor. Make sure you are using properly rated test leads and that the appliance is powered on for this test.
• If the voltage reading matches the expected value (typically 120V or 240V depending on your system), power is reaching the component. If not, there may be an electrical issue upstream.

5. If you identify a faulty component or are uncomfortable performing these tests, consider consulting a professional technician or replacing parts as needed. You can find replacement AC unit parts at AppliancePartsPros.com.

Faulty blower motor

The blower motor pushes the cooled air through the ducts and into your living spaces. If the motor is malfunctioning, the AC unit might run without actually blowing air.

Troubleshooting the blower motor

1. Turn off the AC unit’s power at the breaker box for safety.
2. Access the blower motor compartment, usually found in the air handler or furnace.
3. Inspect the motor for visible signs of damage, wear, or overheating.
4. Check the motor’s belt (if applicable) for fraying, looseness, or breakage. Replace the belt if necessary.
5. Test the blower motor using a multimeter:

• Set the multimeter to measure resistance (ohms).
• Disconnect the motor from the circuit by unplugging it or disconnecting the wires.
• Place the probes on the motor’s terminals to measure the resistance of the windings.
• Refer to your unit’s service manual for the correct resistance values. Typically, a functioning motor will have a specific resistance value; if the reading is infinite or zero (no resistance), the motor may be faulty.

6. Note: Do not use continuity mode when specific resistance values are needed. Resistance testing is crucial for diagnosing motor windings.
7. If the motor fails the resistance test, it may need to be replaced. You can find replacement AC unit blower motors at AppliancePartsPros.com.

Safety precautions: Always unplug the appliance or turn off power before testing for resistance or continuity to prevent electric shock. Refer to the manufacturer’s instructions for specific details.

Preventative maintenance tips

Regular maintenance can prevent many common AC issues.

Schedule routine cleanings

• Clean or replace air filters every 1-3 months.
• Inspect and clean evaporator and condenser coils annually.
• Keep the area around your outdoor unit clear of obstructions.

Monitor your system’s performance

• Pay attention to unusual noises or changes in airflow.
• Check your thermostat settings regularly.
• Keep an eye on your energy bills for unexplained increases.

For more detailed troubleshooting, explore our guide on how to troubleshoot & fix common window air conditioner problems.

When to seek additional help

If you’ve tried these DIY solutions and your AC still isn’t blowing air, don’t sweat it. We’re here to help you find the right parts and offer guidance on more complex repairs.

Identifying your AC’s model number is vital for finding compatible parts. If you need assistance, visit our page on how to find your appliance’s model number.

Stay cool with AppliancePartsPros.com

At AppliancePartsPros.com, we’re dedicated to helping you keep your home comfortable. With a vast selection of replacement parts and expert repair advice, we’ve got you covered. Explore our extensive inventory of AC unit parts to find exactly what you need. While you’re waiting for your new part to arrive, you can explore our DIY blog and watch thousands of video tutorials on our YouTube channel. Be sure to follow us on Facebook, Twitter and Instagram to see our latest repair guides!