Sometimes, the mechanical resistance to the motor rotation causes an excessive electric current that can overheat and prematurely damage the blower motor resistor. For example, this happens when the fan blade is jammed by a foreign object or when the motor bearings are worn out and it doesn't spin freely.
Why is my blower resistor keep burning out?
I finally found the simple solution and ultimately the actual cause to the issue of the blower resistor burning out and over-heating the plug wiring - The blower motor itself is the culprit! After years of replacing the blown resister module 3 to 4 a year, I finally bit the bullet and bought a new blower fan/motor.
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.
Why is my blower motor wires getting hot?
That looks like it is caused by loose or poorly crimped connections. It is also possible that the connector tabs are not the right thickness for the connector contacts. The high current causes heating due to resistance caused by the loose connection.
Does a blower motor resistor have a fuse?
A fuse is often located on the resistor board. The fuse only protects the low and medium blower speeds. High speed will still work if the resistor fuse is blown.
Does the blower motor resistor control heat?
The blower motor resistor is an electrical component that is a part of the vehicle's heating and air conditioning system. It is responsible for controlling the blower motor's fan speed.
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.
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 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.
Should you replace blower motor and resistor at the 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.
Why does my blower motor keep failing?
Blower motor breakdown can be the result of anything from old age to failed bearings, high amp draw, electrical failure in the windings, dirt accumulation, and more. “The most common cause is dirt accumulation due to lack of maintenance,” said Tom Beaulieu, president of Bay Area Services Inc.
How does a blower motor resistor work?
The change in resistance controls the current through the blower motor, which in turn limits the speed that the blower motor spins at. When high speed is requested, the blower motor resistor is bypassed and the blower motor ground circuit is connected directly to ground.
Can you repair a blower motor resistor?
The average cost to replace the blower motor resistor at a repair shop is between $44 and $55 in parts and $70 in labor costs, for a total cost of around $114 to $125. On the other hand, you can easily fix the blower motor resistor at home in about an hour (even if you're a beginner) and for around $70.
What does the blower motor resistor control?
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.
Is there a fuse for the heater blower?
Many vehicles have two fuses for the blower motor, one in the interior fuse block and the other under the hood. The blower motor is usually under the dashboard on the passenger side.
Can a bad blower motor cause no heat?
Problems with Your Blower Motor or Blower Motor Resistor Without it, there's no circulation of air—hot, cold, or otherwise. The blower motor resistor is the part that controls the fan speed of the blower motor. Both of these components can fail, resulting in the heating system simply not working.
What happens when a resistor goes bad?
When a resistor fails, it usually gets charred or burns. As a result, it either stops conducting the electrical current/signal or does not resist the current flow.
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.
Can I bypass cooling fan resistor?
The high speed circuit has no series resistor, the Fan Resistor, and needs a 50A fuse. If you short out/bypass the Fan Resistor you may exceed the 30A fuse value. If you replace the 30A fuse with a 50A fuse you may exceed the wires current rating associated with it if it is not the correct gauge wire.
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.
What does a blower motor relay do?
In a blower motor, the relay supplies the power that allows the fans to circulate warmed air. Essentially an on/off switch, the blower motor relay's reactions start and end the heating process in HVAC systems by controlling the flow of current between the power source and the motor.
Can a bad blower motor cause overheating?
A bad blower motor will sometimes overheat, causing a “hot” smell to come out of your air vents. In the worst scenarios, your blower motor may actually start to burn.
Why do I have to hit my blower motor to work?
Blower motor only start working after i hit a bump. In most cases that is a sign of worn down blower motor brushes not making a good contact. In some cases the blower motor/resistor pigtail could cause erratic operation of the blower motor too.
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.
Can a bad blower motor cause overheating?
A bad blower motor will sometimes overheat, causing a “hot” smell to come out of your air vents. In the worst scenarios, your blower motor may actually start to burn.
Can you 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.
What causes a blower motor resistor to go bad?
Corrosion and overheating are the top reasons for a faulty blower motor resistor. Also, the mechanical resistance caused due to a foreign object can overheat the resistor and damage it over time. How much does a blower motor resistor cost?
What causes an electric motor to overheat?
Electrical overload caused by excessive voltage supply or overwork by drawing more current will lead to overheating issues. As the motor works harder or under unusual load, heat will be the chief byproduct, leading to failure.
What causes a heater fan to stop working in a car?
In some cars, a failed blower motor resistor can cause a heater fan to stop working completely. In most cases, a blower motor resistor fails due to corrosion or overheating.
What does it mean when a blower motor has reduced airflow?
Reduced airflow is when the blower motor is trying to move air through the vents but the resistor isn’t sending enough power to move the air with much pressure. Depending on how much resistor is still functioning, the reduced airflow could be an intermittent problem. Will blower motor work if resistor is bad?
Below you will find two interesting articles on a similar topic 👇
Why does my fan resistor keep getting hot?How do I know if my blower motor capacitor is bad?
