What Causes a Blower Motor Resistor to Burn Out?

The blower motor resistor is responsible for regulating the voltage and frequency of your blower motor, and if it fails, the entire blower electric setup will fail. The resistor can fail due to several reasons like a worn-out blower motor, water, leaves, any dirt at the blower inlet, and high electric current than required at the resistor. This article is all about checking and replacing your car’s bad blower motor resistor.

Blower motor resistors is an electrical component in blower that controls the speed of the blower motor. It control the motor speed my regulating the flow of current through the electric circuit.

Blower motor resistors can burn out over time if the motor spends a lot of time running at high speeds. Rotating at high load/speed over heat the system resulting in either partial or complete burn out of resistor

Overheating can even cause the entire blower setup to fail and that’s why it’s important to keep blower motor resistors in good condition by regularly checking them and replacing them as needed.

In this article, we’ll explain what a blower motor resistor is, how it works, and the signs that it’s starting to burn out. We’ll also provide some tips on how to fix it if it’s defective.

Causes a Blower Motor Resistor to Burn Out:

As resistor work to regulate the flow of electric current through the electric circuit and flow of electric current produces heat. If that heat goes over a certain limit then it can easily damaged the blow motor resistor. To avoid this, manufacturers usually mounts the blower motor resistors in the heater ducts, causing cold air to flow over the resistor.

Even with continuous flow of air over it, the resistor can still burn out and it is mainly due to following reason.

Worn Blower Motor

If you are experiencing problems with your blower motor resistor, there is a good chance that it is due to a worn blower motor. This component is designed to protect the motor from overcurrent and overheating, but if it becomes worn, it can cause the motor to overheat and burn out. 

When the worn blower motor causes the blower motor resistor to burn out, it can happen in a few different ways. The most common way is when the worn blower motor overheats and starts to damage the resistor. Over time, this can cause the resistor to heat up and eventually fail. Another way is when the worn blower motor creates a lot of vibration, which can also damage the resistor.

High Resistance in the Electrical Connector

When a bad electrical connector is inserted into a circuit, the high resistance causes a blower motor resistor to burn out. This is because the current flowing through the resistor is too high for it to handle, and eventually it will fail.

This is why it is important to make sure that the connector with good working condition is properly installed and that the resistance of the electrical circuit is within safe limits. If the resistance of the circuit is too high, it can cause damage to the equipment and potentially the user.

Water, Leaves, and Debris in the Airflow

If the airflow within a car is obstructed by leaves, water, or debris, the blower motor will overheat and eventually burn out. This is because the blower motor is tasked with moving air across the combustion chamber to boost the efficiency of the engine. 

When the airflow is blocked, the motor is forced to work harder and over time, it will eventually wear out. This can happen even if the car is not in use, and it is important to have it serviced regularly to avoid future problems.

Cost of Repairing a Blower Motor Resistor

If you replace your car’s blower motor resistors yourself, then the labor cost will be zero and overall repairing cost will reduce. In this case, you just have to bear the cost of the equipment. If you resort to a mechanic, your costs will increase significantly.

However, the cost of replacing a blower motor resistor is $50 to $60 for parts and $60 to $70 for labor costs, totaling around $120 to $140.

Blower Motor Resistor
Blower Motor Resistor

How to Fix a Blower Motor Resistor?

In the case of automobiles, one should seek the help of a skilled mechanic to solve even the slightest problem. But to be honest, in some cases, you can solve the problem yourself if you want. For example, in the case of a blower motor resistor, you can fix it yourself if you follow our recommended steps correctly.

Fixing a Blower Motor Resistor infographic

Step 1: Pull out the Glove Box Cover

First, you need to remove the glove cabin and no specific tools are required for this. If you just push from the side, it will move out of the dashboard. However, some car exceptions require equipment to complete the task.

Step 2: Detach the Wiring Harness and remove bad resistor

Since the blower motor resistor position varies from vehicle to vehicle, in some cases, you may need to eliminate the harness first and then go for the resistor In contrast, other cars have to pull off the resistor without working on wiring harness.

Step 3: Remove the Blower Motor Resistor and Replace it 

Once you have the bad resistor in front of you, remove that bad blower motor resistor out of your car’s Heating, Ventilation, and Air Conditioning (HVAC) housing.

Some blowers have foam or rubber gaskets on the outer end of the motor resistor. Notice if your new one also has it. If so, you will need to completely discard the blower motor resistor.

Now you can install the new blower motor resistor. Before closing the setup, make sure that the blower motor fan rotates at the correct speed after installing the new resistor. If everything is OK, then you can proceed to the final steps of resistor installation.

Step 4: Fasten Screws and Reconnect the Wiring Harness

As you are sure that your blower motor is now working properly, tighten all the locks and reconnect the harnesses. Reconnect and reinstall all the parts you removed in the second step.

Step 5: Put Back the Glove Box Cover

As everything is in its place, you can now put back the car Glove box cover. You are now good to go.


A blower motor resistor is a component that helps regulate the voltage that goes to the motor. When it fails, this can cause problems with the motor, potentially the result is that the blower motor relay keeps burning out. Depending on the location of the resistor, it can be relatively easy to replace, or more expensive to repair. 

In either case, it’s important to know what causes it to fail in the first place so that it can be fixed as soon as possible. If you’re experiencing problems with your blower motor, be sure to get in touch with a professional for help. Or, by following the easy steps discussed in our article, you can do it yourself no doubt.

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William Baldwin

This Is William Baldwin, The Founder & Managing Editor of this website. Me and my team share automotive tips, tricks, and news

Fact Checked And Mechanically Reviewed By


Talha Atta

Talha Atta, a Mechanical Engineer and experienced technical content writer and editor at Autoglobes.com with a passion for the automotive industry.