What Causes a Blower Motor Resistor to Burn Out?

Blower motor resistors can burn out over time if the motor spends a lot of time running at high speeds or if it’s run for a long period without stopping. When this happens, the resistor shorts out, which causes the motor to overheat. Overheating can cause the motor to fail, which is why it’s important to keep blower motor resistors in good condition by regularly checking them and replacing them as needed.

If you’re experiencing problems with your blower motor, that the blower motor resistor keeps burning out, you likely have a blower motor resistor burning out. This component is responsible for regulating the voltage and frequency of your blower motor, and if it starts to fail, it can cause major problems. 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:

OK, a summary of the work of a resistor shows that it interferes with the passage of electricity. We can compare its function with a flow regulator in a pipe. Since resistors can reduce current, they can generate a lot of heat. 

This heat generated at one time goes out of range and the resistor burns out. To avoid this, manufacturers mount blower motor resistors in the heater ducts, causing cold air to flow into the resistor. Reasons why a blower motor resistor burns out:

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 an 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 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 want to replace your car’s blower motor resistors yourself, your costs will be reduced. In this case, you just have to bear the cost of the equipment. However, 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.

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. Again some cars do not need to remove the glove cabin in this case.

Step 2: Detach the Wiring Harness, then Unscrew the Screws

Since the blower motor resistor position varies from vehicle to vehicle, in some cases, you may need to eliminate the harness initially. In contrast, other cars have to pull off the resistor first and then detach those.

Step 3: Remove the Blower Motor Resistor and Replace it 

Since you have removed all screws and detached the wire harness, now slide the 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 discarded blower motor resistor.

Now you can install the recent blower motor resistor. Before fully installing, make sure that the blower motor fan rotates at the correct speed by fitting the resistor in the initial test. If everything is OK, then you can proceed to the final installation.

Step 4: Fasten Screws and Reconnect the Wiring Harness

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

Step 5: Put Back the Glove Box Cover

Whether your car falls into the category of having to omit the glove box in case of fixing the blower motor resistor, you will need to reinstall the glove box door.

Conclusion

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.