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Blower Motor Resistor

Blower Motor Resistor Explained!

What is a Blower Motor Resistor? its Application, Symptoms, & How It Works.

A blower motor resistor is an essential electrical part of an automobile’s heating, ventilation, and air conditioning (HVAC) system. Usually, it’s a compact, rectangular device with many resistors of varying resistance integrated into it. This component’s main job is to control the blower motor’s speed, which in turn manages the HVAC system’s fan speed.

They can be changed mechanically or electrically by the air conditioning system to alter the fan speed. When a resistor fails, the fan will run only at higher speeds or at its highest speed.

The applications of a blower motor resistor include the following:

  • This resistor is used to control the speed of the blower motor within a car.
  • This resistor controls the flow of current throughout the blower motor.
  • These resistors are used in automobiles.
  • Actually, this resistor is a solid-state module that transmits a varied signal toward the blower motor.

The blower motor resistor is located under the dashboard or under the glove box and is responsible for controlling the speed of the blower motor fan. It is connected to the air conditioning system and can be found under the dashboard or under the glove box.

The resistor controls the speed of the blower motor when the fan speed on the instrument cluster is adjusted.

It undergoes significant wear due to frequent fan speed adjustments and could fail due to ongoing stress. The fan speed, interior temperature, and other factors affect the amount of air blowing through the dashboard vents. By limiting electrical current to the blower motor, resistors regulate fan speed.

The blower motor resistor works between the heater, AC, and electric fan controls and is typically mounted under the dash, on the opposite side of the steering wheel, and near the electric fan to keep the fan cool while in use.

The blower motor resistor is a crucial component in controlling the speed of the motor, enabling it to transmit a varied signal. It is inbuilt with various resistors, connected in series through the motor assembly, regulating current flow throughout the motor.

Each fan speed range can be connected to one or multiple resistors, limiting the motor’s rotation speed. When the maximum speed is requested, the resistor moves around and the motor’s ground circuit is connected directly to the ground, allowing high current to flow throughout the motor and achieve maximum speed.

A blower motor resistor can be tested using a multimeter. Before testing, visually inspect the resistor for signs of rust and hot burns. If overheating connectors are detected, change the resistor.

To quickly gauge the resistance of the resistor, connect one of its probes to the common output port of the resistor. Calculate the resistance between the input and output terminals. Identify the common terminal and which terminal controls the speed. This process ensures proper wire fusion and prevents overheating.

This process helps identify if the Blower Motor Resistor is faulty and ensures the system’s functionality.

This can lead to the fan not operating at all or with only a small amount of air passing through the vents. The electrical circuits need to be examined to diagnose the issue, as numerous components that could cause the same issues are present.

Blower motor resistors can be damaged due to corrosion or overheating, making it difficult to adjust the airflow speed. In some cases, the fan’s blower motor, switch, or resistor may be faulty, causing the fan to run at its highest speed.

Common symptoms of a blower motor resistor: this sign can often be detected as a potential issue, indicating a potential problem with the blower’s performance.

Blower Motor Stuck at One Speed: The blower motor resistor, responsible for controlling fan speed, can be a bad issue in HVAC systems. Symptoms include the motor stuck at a specific speed.

To fix this, replace the resistor and other bad HVAC parts. Despite using the heater or AC, the motor must be replaced to ensure proper functioning.

No Air Coming From a Car’s Vents: Another symptom of a failing blower motor resistor is a lack of air from the vehicle’s vents, indicating a problem with the blower motor resistor, which is responsible for transferring power to move air with specific pressure.

The Blower Motor Does Not Work in Certain Settings: Moreover, another common symptom of a blower motor resistor is the failure of the motor not functioning in certain settings.

This can be due to internal components malfunctioning or a faulty switch controlling the motor’s function. A proper diagnosis is recommended to determine the root cause of the issue.

Blower Motor Resistor Repair Cost: In the UAE, the cost of a blower motor resistor varies between AED 150 and AED 200, depending on the vehicle type.

The blower motor resistor is a part in an air conditioning system that plays a significant role in maintaining the efficiency and safety of your heating system.

If the resistor fails, it may be due to issues with the blower motor itself. To diagnose the issue, inspect the resistance between the terminals and compare it with specifications. If the resistance is not within specifications, replace it.

The cost of replacing the blower motor resistor can range from $10 to $60 depending on the type of car you drive. Labor prices for this replacement can vary, so it’s advisable to compare quotes to avoid paying more than you should.

The total cost for parts and labor is typically between $50 and $200, but the blower motor resistor can be easily and quickly fixed at home for about $60.

To replace the blower motor resistor, follow these steps:

1. Remove the glove box door if necessary.
2. Disconnect the wiring harness and unscrew the screws.
3. Remove the faulty resistor and replace it with a new one.
4. Test the new resistor by loosely installing it and ensuring all fan speeds function as intended.
5. Tighten the screws and reconnect the wiring harness.
6. Reinstall the glove box door if necessary.

In summary, the blower motor resistor is a vital component in maintaining the efficiency and safety of your air conditioning system. If you’re not confident in doing it yourself, consider hiring a qualified mechanic for the job.

Blower Motor Resistor Video

FAQs

What causes a blower motor resistor to fail?

They fail when on their own quite often when the blower motor repeated failures or excessive current draw, often caused by tight bearings, can cause overheating when restricted airflow is present, leading to frequent failures.

How do I know if my motor resistor is bad?

The fan works on high speed but not on other speeds, indicating a potential issue with the blower resistor’s thermal fuse, requiring a complete replacement.

Does the blower motor resistor affect AC?

The work of an HVAC system can be affected by a bad blower motor resistor, which can impact both heat up and cool down, and if the fan works properly, the temperature may not be reaching.

Related: Shift Interlock Solenoid Explained!

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