How to troubleshoot a blower motor problem?

Signs of a Bad Blower Motor Resistor Loss of HVAC fan control (total or certain speeds) The fan only works on its highest speed setting. No air coming from vents. Intermittent or inconsistent fan speed. A Brief Guide To Troubleshooting A Malfunctioning HVAC Blower Motor Checking The Power. As with most electrical or electronic devices that are completely failing to operate, the first step... Checking The Windings. If debris is not the issue, it’s time to get out the multimeter and check for AC voltage across... Checking The Capacitor. If the motor windings seem to be... More ...

How do I know if I need a blower motor or a resistor?

Signs of a Bad Blower Motor Resistor Loss of HVAC fan control (total or certain speeds) The fan only works on its highest speed setting. No air coming from vents. Intermittent or inconsistent fan speed.

What can cause a blower motor to stop working?

In most cases, a blower motor resistor fails due to corrosion or overheating. Sometimes, the mechanical resistance to the motor rotation causes an excessive electric current that can overheat and prematurely damage the blower motor resistor.

Is there a fuse for the blower motor?

What happens when the blower motor resistor goes out?

If the resistor shorts or fails, it may cause the blower motor to remain stuck on one fan speed. The heating and air conditioning systems may still function at one speed, however the resistor will have to be replaced in order for full functionality to be restored.

Will a blower motor work without the resistor?

Without any power, the motor won't run. As a result, the blower fan stays still and silent, and no air blows out of the vents. There are instances where a bad resistor will prevent the current from reaching the blower motor altogether.

Should you replace blower motor and resistor at the same time?

We do suggest that you replace the resistor at the same time. It may not be critical, but this will keep the system more uniform. The issue may even be related to the resistor. If you know that it is not related to the issue, then you do not have to replace it.

Where is the blower motor reset button?

Locate the reset button on the furnace and press it to reset the furnace. It is usually located inside the blower compartment on the side of the blower motor. Be cautious as the housing may be hot. If the button is popped up, press it down.

How do I test a blower motor resistor?

Place one lead of the Ohmmeter on terminal 1 of the resistor. Place the other lead on terminal 2 and check against specifications. If this circuit is open, showing infinity on the Ohmmeter, the blower resistor must be replaced. Move the lead from terminal 2 to terminal 3 and check this reading against specifications.

How do you test a blower motor with a multimeter?

Turn off your vehicle, set your multimeter to Ohms, and check for resistance between the blower's positive and negative terminals. You may also turn the car key to run without starting the engine, put the cooling system at full blast, and check for DC voltage. If none of these produces a reading, the blower is bad.

How do you reset a furnace blower motor?

Locate the reset button on the furnace and press it to reset the furnace. It is usually located inside the blower compartment on the side of the blower motor. Be cautious as the housing may be hot. If the button is popped up, press it down.

What causes heater blower not working?

If little air is coming through the vents (hot or cold), then it could be because the blower motor for the fan or a switch or resistor that controls fan speed isn't working. Another cause might be that the electronically controlled “blend doors” that direct air flow are stuck or broken.

How do you test a blower motor resistor?

Place one lead of the Ohmmeter on terminal 1 of the resistor. Place the other lead on terminal 2 and check against specifications. If this circuit is open, showing infinity on the Ohmmeter, the blower resistor must be replaced. Move the lead from terminal 2 to terminal 3 and check this reading against specifications.

Where is the blower motor relay fuse located?

Under the instrument panel, look under the glove box. On the right side of the fender wall you will find another fuse box. The blower motor fuse is easy to replace.

What relay controls the blower motor?

The blower motor relay controls the current used to power the blower motor, and is subject to the constant on and off switching.

Does a blower motor have a relay?

In a blower motor, the relay supplies the power that allows the fans to circulate warmed air. Essentially an on/off switch, the blower motor relay's reactions start and end the heating process in HVAC systems by controlling the flow of current between the power source and the motor.

Where is the blower fan resistor located?

The blower motor resistor is usually extremely easy to access, but the hard part can be positioning your body inside the car to remove the part. The resistor is at the bottom of the HVAC housing or just behind the glove compartment.

What is the difference between blower motor and blower motor resistor?

The blower motor resistor is responsible for controlling the blower motor speed. In the past, this was done by varying the voltage supplied to the blower motor. In newer applications, the blower motor resistor is actually a solid state module that sends a varied signal to the blower motor.

Can a bad blower motor cause no heat?

Problems with Your Blower Motor or Blower Motor Resistor Without it, there's no circulation of air—hot, cold, or otherwise. The blower motor resistor is the part that controls the fan speed of the blower motor. Both of these components can fail, resulting in the heating system simply not working.

Can you reset a motor?

Once the motor has cooled sufficiently it can be re-started, usually by pushing the popped-out reset switch back down. If the motor turns off again on re-set you should not keep running it as it may be damaged and the system may be unsafe.

How do you test a blower motor with a multimeter?

Turn off your vehicle, set your multimeter to Ohms, and check for resistance between the blower's positive and negative terminals. You may also turn the car key to run without starting the engine, put the cooling system at full blast, and check for DC voltage. If none of these produces a reading, the blower is bad.

Where is the blower motor capacitor?

It's common for HVAC blower unit fan motors to use a start/run capacitor. Those will be located in the blower cabinet, often right on the blower motor itself.

How much does it cost to replace a blower motor resistor?

How much does a blower motor resistor cost? To replace the blower motor resistor, it would cost you anywhere between $50 to$150 – this includes the cost of equipment and labor. However, by doing it yourself at home, you can save up to $70.

What does blower motor reset button look like?

These blowers can be VERY hot. Step 4: Locate the reset button. This is usually on the side or the back of the blower motor. Often times, this button is red.

Can you run furnace without blower?

The blower fan motor The furnace can produce heat inside the combustion chamber—but that heat won't go anywhere if the blower fan isn't running. Because there's a danger of the furnace overheating without the blower fan, the furnace won't operate unless the blower has power.

What happens when the blower motor resistor goes out?

If the resistor shorts or fails, it may cause the blower motor to remain stuck on one fan speed. The heating and air conditioning systems may still function at one speed, however the resistor will have to be replaced in order for full functionality to be restored.

How do you troubleshoot an HVAC blower motor?

When troubleshooting your HVAC blower motor, check your power, windings, thermostat, capacitor, and filter and vents. These are some common ways of troubleshooting the issue of your blower motors. In this article, you will learn more about the HVAC Blower motor and what it does.

What causes a blower motor to go bad?

Otherwise, normal old-age issues, such as bearing failure, cause seizing, which leads to massive electrical failure. A less common cause is insufficient voltage to the blower.”. The first step in diagnosing blower motor failure is to check to see if there is demand for the blower.

Why won’t my air conditioner blower work?

Lots of times, airflow restriction from a dirty filter will cause a blower motor to overheat. The excess heat in the motor will cause its performance to degrade, and the motor may fail altogether. If your blower has a fan belt, take a loot at it. If the belt is snapped, then the blower won’t work. Replacing the belt is a fairly simple fix.

What should I do if my furnace blower is blowing cold air?

If the filters, belt, and capacitor look good, the next thing to do is to check out the blower motor itself: Turn off the power to your furnace and remove the cover from the blower compartment. Inspect the blower motor and look for any damage. Give the blower fan a spin with your hand to see if there is any scraping or wobbles.