How To Test A Furnace Blower Motor? Top Troubleshooting Tips

Rima Chatterjee


Furnace blower motors form an essential part of HVAC systems. To ensure efficient operation and avoid costly repairs, it is important to test these motors. You can start by disconnecting the power supply and using a multimeter to check resistance values and voltage. Furthermore, inspect the blower wheel for dirt buildup and the capacitor and control board for any signs of damage or wear.

Testing your furnace blower motor involves some simple steps and the use of essential tools such as a multimeter. Start by switching off the thermostat face or fuse panel. Then move on to testing individual motor components such as capacitors and windings, as well as checking for short circuits or resistance readings.

If your HVAC system is not working as expected, it may be due to a damaged ECM blower motor module. This can happen due to regular wear over time. To make sure that your furnace blower motor is not bad, check for less hot air than what your ex posts on social media!

How To Test A Furnace Blower Motor

Common Signs of a Bad Blower Motor

As the temperature drops, your furnace blower motor is key to keeping your home cozy. But how do you know if it’s not running smoothly? Here are a few signs to look out for:

  1. Weak airflow from the vents. This could mean the blower motor is malfunctioning. Dirty air filters and ducts can also cause this, so be sure to check those first.
  2. Unusual noises like grinding or banging coming from the HVAC system. These sounds are usually caused by worn parts or an unbalanced blower fan.
  3. Short cycling of the blower motor. On and off frequently? It could mean an issue with the capacitor or control board.

Be aware that each HVAC system is unique and may display different signs of a bad blower motor. Don’t wait until your home is left without heat – contact a professional HVAC technician to test the components and identify the issue. Don’t let a small problem snowball into costly repairs or even worse – total system failure! Take action now for a stress-free winter.

Tools Required to Test Furnace Blower Motor

Testing a furnace blower motor requires the right tools. You’ll need a multimeter to measure voltage, resistance, and current. A capacitor tester is good for confirming the correct voltage to the motor module. And, don’t forget a thermometer to check the temperature rise of the motor.

Firstly, turn off all power sources. This is super important for safety. Secondly, remove the wires from the terminals one by one. Make sure to note where each wire is connected. Lastly, test the resistance at two different speeds using a multimeter.

If everything looks okay and your heating system still isn’t working, it’s time to call a professional. My dad always said it’s best to have spare parts on hand and be incredibly cautious when dealing with high-voltage power supplies. He was an HVAC technician for 40 years; this tip saved his life!

Steps to Test a Furnace Blower Motor

Testing a furnace blower motor is key for a successful HVAC system. Here’s how:

  1. Safety first: Turn off the power and disconnect all wires.
  2. Check the wiring and capacitor: Use a multimeter to test the continuity between the speed and common wires. Inspect the capacitor for any leaks or bulges, or use a capacitance tester.
  3. Examine the motor windings: Use a multimeter to check for indications of damage or wear. The resistance values should be the same as in your model’s manual.

Reconnect all parts and turn on the power. See if weak airflow or other issues have improved.

It’s important to note that testing procedures differ depending on the make and model. ECN blower motors have their own module that controls their speed, making testing more complex.

As an HVAC technician, I once arrived at a client’s home after they complained about no cold air from their vents. After investigating, I saw their blower motor’s burnt-out squirrel cage part. I replaced it and ran tests. Their air conditioning was up and running again!

Furnace blower motor issues can be as annoying as a mosquito on a camping trip.

Troubleshooting Common Furnace Blower Motor Issues

Fixing a faulty furnace blower motor can be tricky. But with guidance and knowledge, it’s possible. To troubleshoot the issue, follow these steps:

  1. Check if power is running to the unit. Reset the circuit breaker or fuse panel if needed.
  2. Look for signs of wear or damage on the component itself.
  3. Test the capacitor. Use a multimeter and check resistance values. Compare to values in the manual. If readings are accurate, rule out capacitor failure. If resistance values seem off, or no change, there may be a short circuit. Contact a professional HVAC service provider for help.

Blower motors have evolved. ECM motors offer variable speeds for energy savings. PSC motors run at a constant speed. SC motors come with start and run capacitors. Knowing the type of motor can help diagnose issues.

Testing a furnace blower motor isn’t fun. But with proper guidance and equipment, you can avoid unexpected issues.


Testing a furnace blower motor is vital. Check the control board and thermostat face for any wear or damage. Replace them if needed. Clean the blower wheel and squirrel cage from dirt build-up. Replace a bad capacitor with a new one. Tighten wiring connections. Test each speed wire individually to verify voltage. Look for signs of short circuits or damaged parts. Consult an HVAC expert for advice.

About the author

Debarghya Roy: A heating systems author, Passionate about energy efficiency and sustainability, Sharing insights and empowering readers through informative blog articles.