How to test blower motor with Multimeter

How to test blower motor with multimeter. An HVAC unit is a need in every home. An HVAC system is the most reliant technology as the season’s change, from summer to winter. A blower motor is a component found in every HVAC system.

How to test blower motor with multimeter

When your heating system is turned on, this blower motor is in charge of blowing heated air through your vents. The engine is also blowing cold air out of the vents.

Continue reading to learn more.

Working of A Blower Motor

The motor works in tandem with your home’s cooling and heating system, and a thermostat keeps track of the temperature in your home.

When the temperature drops below the temperature set by the thermostat, it sends signals to the furnace, which turns on. The stove generates cold or hot air, circulated throughout your home.

The blower is in charge of moving the cold or hot air produced by the furnace throughout your home, ensuring that the temperature is maintained at the desired level.

This is made feasible by the blower motor, which spins a fan. The variable-speed engine is the optimum form of blow motor to use between single-speed and variable-speed motors.

The single-speed motor is always relegated to chilly sports because it only operates when the thermostat signals it. On the other hand, the variable-speed engine keeps the room at a suitable level by blowing cold or hot air at different rates.

Things To Consider Before Testing A Blower

If you’re having trouble with your HVAC system, it’s likely that your blower motor is broken and has to be replaced. The following are some of the signs of a faulty blower motor:

1. If you can’t get any air out of your vents

It could be malfunction if you don’t get air from your vents when the air conditioner or heater is turned on. When your blower motor fails, it means no air will be circulated, necessitating testing or replacement.

2. If you have any of the following: Your vents have poor airflow

If the airflow in your vents is weak or non-existent, your blower motor may be failing. A softer or broken blower motor will not be able to provide enough airflow to keep your cabin at a comfortable temperature.

3. Fan speed has been reduced

If the motor only works at a set speed, this is another sign of a faulty blower motor. The bulk of blower motors is designed to function at various speeds to manage multiple house temperatures properly. It’s a symptom that your blower motor is broken if it can’t push cold or heated air at its intended settings.

Testing a blower motor using a multimeter

The blower motor is typically found behind the glove compartment in your car. The first step is to disconnect the positive and negative power supplies.

  • Normally, the black wire is negative. To test the negative black cable with your multimeter (Ohm scale), take the positive lead of the multimeter.
  • Turn on your engine with the ignition key. to read the purple wire for current
  • After you’ve set your multimeter to DC power, turn on your heater or air conditioner to maximum power.
  • Your blower motor is malfunctioning if your multimeter reads no current.
  • The blower motor should be tested further. if the multimeter detects a current
  • Then, in the footwell, remove the fuse panel access cover, which is located next to the passenger’s side shifter.
  • Remove the blower motor relay from the vehicle. With your multimeter, check the grounded relay (Ohm scale). Then, check it without dropping the current pin to the multimeter’s DC scale.
  • If you don’t see any current, look under the hood for the IGN fuse, remove the cover panel, and connect it to the negative side of your battery with a voltmeter. If the fuse is blown, it is recommended that you replace it.
  • Check the connector if the fuse works. Test the connector with your car’s ignition running and a multimeter set to the DC scale. Using a multimeter, check the fuse. multimeter


In this article, we spoke about how to test a blower motor using a multimeter. Blowers are used in practically every household, so if you’re having trouble with yours, read our guide for the best advice.

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