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.The blower motor resistor controls the power to the system’s blower motor. When it fails, it can cut off all power to the motor. When the blower motor doesn’t get power, air pressure can’t be produced.
How do I know if my blower motor resistor is bad?
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 causes blower motor resistor failure?
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.
What does blower motor resistor do?
Blower resistors are resistors which are used to control the fan speed of automotive blowers. The fan speed can be changed either by switching the blower resistor resistance mechanically using a rotating lever, or electronically by the air conditioning system.
What happens when blower motor goes bad?
If the blower motor is completely bad, then you'll have no airflow at all. Strange sounds coming from blower. Blower motors can make all kinds of sounds, depending on what the issue is. Vibrations, grinding, and high pitched-noises are some of the sounds a blower can make if it's going bad.
How do I know if my blower motor resistor is bad?
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 causes blower motor resistor failure?
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.
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.
Is there a way to 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 long should a blower resistor last?
How long should a blower motor resistor last? While a blower motor resistor is built to last for the car's lifespan, you can expect it to last for 10-15 years, but it's possible for them to last longer or shorter depending on the climate, driving habits, and quality of the resistor.
How long should a blower motor resistor last?
The blower motor resistor is designed to last for the car's lifespan. In most cases, these resistors will wear out long before the car does. Usually, the wear that the blower motor resistor has is due to the constant use that it gets and the heat that it is exposed on a regular basis.
How much does it cost to replace 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.
Is there a fuse for blower motor?
What does a bad blower motor sound like?
A defective blower motor will make a continuous sound noticeable by the passengers in the vehicle. It can manifest as a knocking, whirring, clunking, vibrating, squealing, or whining noise that persists until the blower motor is replaced.
When should I replace my blower motor resistor?
The most common symptom of a bad blower motor resistor is that you will only notice that your blower is working on the highest speed setting or that it won't work at all. The main symptoms of a bad blower motor resistor include: Only One Speed From Blower Motor. Various Airflow Settings Not Working.
Is there a fuse for blower motor?
What does a bad blower motor sound like?
A defective blower motor will make a continuous sound noticeable by the passengers in the vehicle. It can manifest as a knocking, whirring, clunking, vibrating, squealing, or whining noise that persists until the blower motor is replaced.
How do I know if my blower motor resistor is bad?
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 causes blower motor resistor failure?
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.
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.
How do you know if a resistor is bad?
A good resistor should test within its rated range. A bad resistor will either show infinite resistance or a measurement far higher than its rated resistance. In either case the resistor is no longer functioning properly.
How do I test a blower fan relay?
Connect a test light or multimeter to the ground (black lead). Turn the ignition key to the on position (engine off), and remove the relay. Using the probe, test all terminal sockets in the relay connector. Two of the four should have power.
Why is my blower fan not working?
If you see or hear the fan turn on, your blower motor is not the culprit. If the fan does not start, you have a wiring issue (circuit breaker trips) or motor problem (circuit breaker does not trip). While your thermostat may be at fault, only an HVAC technician can diagnose and remedy the issue correctly.
Should I replace the blower motor and resistor at 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.
How do you test a resistor?
To test individual resistor values (outside a circuit), connect the multimeter probe wires to the resistor's two terminals—it doesn't matter which way round, as resistors are not directional components. Make sure the multimeter dial is in resistance measuring mode. Then check the value on the multimeter.
Does blower motor resistor affect AC?
A failed blower motor resistor can cause issues with the operation of the entire heating and air conditioning system.
What happens if you have a bad blower motor resistor?
A damaged blower motor resistor will work on one fan speed which may not be enough to keep the inside of your car cool or warm enough. If the airflow from the vents only blows at certain speeds…
Why is my blower motor stuck on one speed?
1. Blower motor stuck on one speed. A common symptom of a faulty blower motor resistor is a blower motor that is stuck on one setting. The blower motor resistor is the component directly responsible for controlling the blower motor fan speed. If the resistor shorts or fails, it may cause the blower motor to remain stuck on one fan speed.
How do blower fan resistors work?
Other car makers reverse that and run power to the blower motor first and terminate ground at the blower fan speed switch. By it’s very nature, resistors resist the flow of electricity, much like a flow restrictor in a pipe.
Where is the blower motor resistor located on a car?
The blower motor resistor works between the heater, AC and electric fan controls and is typically located under the dash, on the opposite side of the steering wheel and near the electric fan to keep the fan cool while in use. Usually, you can witness some signs of a bad blower motor resistor that can alert you to the potential issue.
Below you will find two interesting articles on a similar topic 👇
What happens if my blower motor relay is bad?How do I know if my blower relay is bad?
