What does a Blower Motor Resistor Do

What does a Blower Motor Resistor Do.  If you are interested in knowing how the bowler motor resistor work, then here you can find all the information about the blower resistor. Controlling the blower motor’s speed is its responsibility. In the past application, the resistor helps limit and regulate the electric current flow in the electronic circuit. When the voltage provided to the blower motor is changed, it is accomplished.

But in the new applications, the solid-state module transmits the signal by changing the call to the blower motor. The signs appear when the resistor is not working, the resistor is failing. It causes the blower motor to be stuck at one fan speed. Only the highest speed is used by the fan. The bad resistor causes the inconsistent speed of the fan.

What does a Blower Motor Resistor Do

The air conditioning and the heating system may function at one speed. To avoid this issue, you should replace the resistor to restore its functionality. Without any power, the motor can’t work. If the blower motor does not have the resistor, then the blower fan remains still and does not run, and it does not allow the air to blow out from the vent.

The bad resistor also prevents the current from flowing toward the blower motor. The resistor in the blower motor, which is in the car, helps push air inside the vent by using the air conditioner and the heater. The strange noises come when you turn it on.

It causes the overheating of the airflow. If you want to replace the faulty resistor, the average cost is between $44 and $55 in parts and labor costs. Then the total labor cost is about $114 to $125. The blower motor resistor helps in controlling the blower motor.

When the resistance is open, it causes an increase in the total circuit resistance and a decrease in the whole circuit current. The relay transforms the power, which allows the fans to circulate the warmed air. You can test the resistor with the help of a multimeter by connecting both terminals of resistance to the probe wires of the multimeter. The blower motor can last for two decades.

Blower motor resistor

The car mostly has common problems. The blower motor resistance fails when the heater fan runs only on the highest speed, 4 or 5, and cannot run at a low rate. When the blower motor resistor damages the car, it stops the heater fan’s working completely. Corrosion and overheating are the two most frequent reasons for blower motor heater failure.

The blower motor resistor can sustain permanent damage from a high electric current. The simple electrical resistor and the blower motor resistor are identical. When a blower motor has four or five fixed speeds, it is used in automobiles.

  •   Inspecting the Blower Motor Resistor

The blower motor resistor used in the car if it has a high four-speed set in car, then the resistor is bypassed, and the blower motor takes power directly from the fan switch. In the blower motor, the bad resistor causes the blower motor to work at a high-speed setting. More resistance added to an electrical circuit reduces the current flowing through it.The total resistance is the sum of the individual resistances when the opposition is connected in a sequence.

  •   Diagnosing the Blower Motor Resistor

In some cases, the blower motor resistor gets damaged because of itself. Therefore, before replacing the blower motor resistor, make sure that it is running quietly and without any noise. Making a screaming noise while operating is one of the most typical signs that the blower motor resistor is failing.

Blower motor resistor testing

It is imperative to try the blower motor if it is not functioning properly. You can test the blower motor resistor quickly with the help of the multimeter. After turning on the blower motor, the voltage on it is typically measured within it. If the reading of the voltage on the multimeter is 4 to 6V at low speed and 12V at high speed, then the motor is defective.

Symptoms of the Faulty Blower Motor Resistor

The symptoms that appear when the blower motor resistor is faulty are given below:

   1. The Blower Motor gets Stuck at only One speed

The resistor on the blower motor is primarily in charge of regulating the fan’s speed. When the resistor is short or fails, it causes the blower motor resistor to be stuck at one rate.

   2. The blower Motor is not Able to Work at the Certain Setting

The resistor on the blower motor is primarily in charge of regulating the fan’s speed.

   3. No Air Comes from the Vehicle Vent

When the blower is faulty, then; as a result, there is no air in the vehicle’s vent. The blower motor has the basis of the blower motor resistor.

So the failure of the blower motor resistor can cause a massive problem for the blower motor resistor when the blower motor is not receiving any power, so it cannot produce the air pressure.


The blower motor resistor is the minor component that causes the problem when it fails. The blower motor resistor adjusts the fan’s speed when it can not change the rate, which may lead to many problems. The resistor is in charge of sending the fluctuating signal.

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