- Only One Speed From Blower Motor One of the most common symptoms of trouble with the blower motor resistor is when the fan gets stuck in one setting. ...
- Various Airflow Settings Not Working On the other hand, you might notice that the fan works in several settings, but not all of them. ...
- No Air Coming From Vents
- Fan does not work at all, so no air comes out of the vents.
- Fan only works on some speeds and not others.
- Fan only works on the highest speed.
- Fan runs all the time and can't be controlled with the fan switch.
- You see smoke coming out of the vents.
What happens when the blower motor resistor goes bad?
What happens when blower motor resistor goes bad? 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.
How do you know if your blower motor is bad?
There are 5 main bad furnace blower motor symptoms to look for:
- Weak airflow coming from the vents. Weak airflow can be an indicator of other problems too such as used up air filters but problems with the motor are a likely ...
- Fully clogged vents. This too can be caused by other issues but is a common symptom for an inoperable blower motor as well.
- Weird sounds. ...
- A high energy bill. ...
- Overheating. ...
How to troubleshoot a blower motor resistor?
How to Troubleshoot a Blower Motor Resistor Locate the fuse for the blower motor in the owners/service manual. Unplug the blower motor and test for power using the 12-volt test light in the same manner as explained in Step 1. Test for ground at the blower motor if there is power indicated at all ranges, but the motor does not function.
How do you replace a blower motor resistor?
- Disconnect negative battery cable.
- Remove right lower instrument panel insulator panel.
- Disconnect blower resistor connector located behind right side of dash.
- Remove blower resistor screws and blower resistor.
How do I test a blower motor resistor?
What happens when blower resistor goes bad?
What causes blower motor resistor failure?
How do you know if a resistor is bad?
How do you know if blower motor is bad in car?
- FAN BLOWS AT ONLY A CERTAIN SPEED. ...
- WEAK AIRFLOW OF THE BLOWER MOTOR. ...
- UNUSUAL NOISES FROM HVAC SYSTEM. ...
- SMOKE OR SMELL WHEN DRIVING. ...
- HOW DOES A CAR BLOWER MOTOR WORK?
Can you fix a blower motor resistor?
Can a bad blower motor resistor cause no heat?
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.Dec 1, 2021
How do you test a blower motor resistor with a multimeter?
What is a Blower Motor Resistor?
In simple terms, a blower motor resistor is an electrical component that can block (resist) the flow of electricity (current) into the blower fan motor. This is how you’re able to alter the fan’s speed—more resistance means the fan won’t spin as fast, which results in less air (hot or cold) being circulated around the cabin.
Signs of a Bad Blower Motor Resistor
Yet while they are pretty darn dependable, like any electrical component, blower motor resistors can go kaput without much warning. Fortunately, it’s pretty easy to diagnose a failing blower motor resistor.
How to Replace a Blower Motor Resistor
While all cars and trucks are different, replacing a blower motor resistor can be a straightforward affair. In our experience, the difficulty all depends on where the blower motor resistor is located. If it’s tucked behind a dash or tight against a firewall, you may have to remove some other parts for access.
What happens if a blower motor resistor is bad?
A bad or failing blower motor resistor hampers the efficiency of the heating and air conditioning system. A working resistor can shift between speed settings according to the user’s preference. If one of the resistors is burned out, the only speeds that will work are the speeds above the burned out resistor.
Why is my blower motor resistor failing?
The most likely reasons for blower motor resistor failure include: Corrosion from long exposure to air and moisture. Overheating—if a motor finds it harder to move because of jamming or worn bearings, it can raise the resistor’s temperatures to dangerous levels. Normal wear due to time and use.
What is the function of a blower motor resistor?
The blower motor resistor controls the fan speed of the blower motor and the resulting change in air pressure produced by the movement of the blower fan. It accomplishes this by regulating the electric current that powers the motor.
Why does my blower fan not blow air out of the vents?
No air comes out of the vents. There are instances where a bad resistor will prevent the current from reaching the blower motor altogether. 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.
How does a blower resistor work?
To understand how the blower resistor works, a simple electrical principle called “ voltage drop ” is used. When a switch, a resistor, and a load are wired in series, the resistor “drops” some of the voltage passing through it, effectively reducing both current flow and volta ge at the motor.
What happens when a blower resistor gets hot?
Blower resistor terminals can develop resistance, and when they do, they get hot and begin to oxidize even further, creating large amounts of resistance where no resistance should be, heating the wire terminals and the wires feeding them until they scorch and melt the blower resistor connector. Eventually, the connector terminals become so damaged ...
What happens if a fan won't work?
Typically, if the fan will work on some speeds but not on others, the resistor is suspect. If the fan won’t work on any speeds except high speed, the blower resistor’s thermal fuse may have failed, meaning the entire resistor needs to be replaced.
How to tell if a blower motor resistor is faulty?
A common symptom of faulty blower motor resistor is when the heating and air conditioning blower only operates at high speed and cannot be adjusted to low speeds. This occurs because the faulty blower motor resistor is not able to control the current flow. It could be that the resistor is somehow bypassed and the current is fed directly from the switch. Excessive current can overheat the blower motor resistor and permanently damage it.#N#In this case, the heating and air conditioning system might still function normally by pushing the cold or warm air out of the outlet alongside the speed. The resistor must be replaced with a new one to restore its function.
What happens when a blower motor resistor goes out?
When the resistor goes out, you might not be able to get any air to come out of the vents. 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. You are left with a heater or air conditioner ...
What is a blower motor resistor?
The blower motor resistor is part of the HVAC system and is an electrical component. It controls the blower motor fan speed. When you adjust the fan speed on the instrument cluster in your vehicle, the resistor is responsible for adjusting the speed that the blower motor runs at. Because the fan speed is regularly adjusted, ...
Why is my blower motor only working at low speed?
This may be due to poor wiring between the blower motor resistor and the blower motor itself.
Why is my blower motor stuck at a certain speed?
Because the blower motor resistor adjusts the fan speed, the inability to change it can point to problems. If the resistor fails or shorts , the blower motor might remain stuck at a particular speed. While you could still use the air conditioning or heater at his speed, you will want to repair it for complete functionality again.
How much does it cost to replace a blower motor?
The average cost of a blower motor resistance replacement is between $80 and $150, and labor costs are estimated between $35 and $80, with the price of the unit between $50 and $75. The estimate does not include taxes and fees.
Where is the heater motor resistor located?
The heater blower motor resistor is often found beneath the dashboard. It is located in the heater and air conditioning compartment. It’s connected to the air conditioning system, where it can adjust the speed of the blower motor fan. It can also be found behind the glove box of some vehicles.
Why does my blower fan not kick on?
This often presents itself as the blower fan not kicking on until the engine is producing a certain level of electric current. The higher current can make the jump across the resistor contacts that are going bad and get the blower motor to engage. The blower motor could stop working again on longer roadtrips when the car is at a cruising speed ...
What is the function of a blower motor?
The resistor of the blower motor is responsible for transferring the electrical current that's required to move air through the vents of vehicle . Blower motor resistors can wear out; the blower motor no longer works correctly if this occurs. There are several symptoms that appear when the resistor of the blower motor is going bad. Recognizing these symptoms and replacing the resistor returns the airflow through the car to the proper levels.
Can a motor blower cause reduced airflow?
Reduced air movement can occur at all of the different speed settings of the motor blower. Depending on how much resistor is still functioning, the reduced airflow could be an intermittent problem. Lynn Rademacher started writing in 2001, covering technology, family and finance topics.
Can a blower motor be lower?
No Lower Settings. The lower settings of the blower motor require less electrical current to engage. But when the resistor of the blower motor is failing, it creates a larger gap between the connectors. This gap may be too far for the electric current to travel across. When this happens, the lower settings of the blower motor aren't able ...
How to tell if a blower motor is bad?
Here are 4 common symptoms of a bad blower motor: 1 Low/no airflow from vents. The classic sign of a bad blower motor is restricted airflow coming from your air vents. If the blower motor is completely bad, then you’ll have no airflow at all. 2 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. 3 Circuit breaker keeps tripping. A blower motor that’s seized up is bound to trip a circuit breaker. (A bad capacitor will trip the circuit breaker too, so be sure to check that first.) 4 Hot/burning smell coming from air vents. 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. Yikes!
What happens if a 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.
What to do if blower belt is snapped?
If the belt is snapped, then the blower won’t work. Replacing the belt is a fairly simple fix. Another thing to check is the capacitor. The capacitor is used to start the fan so it’s worth checking if your blower motor won’t start up.
Why does my furnace blower motor go bad?
Another reason why a blower motor might go bad is due to rust in the motor’s internal components. Rust in a blower motor is a symptom of a dirty blower motor. This is why it’s important to change your air filters regularly and make sure that there are no air leaks in your furnace.
Why does my blower motor overheat?
Lots of times, airflow restriction from a dirty filter will cause a blower motor to overheat. The excess heat in the motor will cause its performance to degrade, and the motor may fail altogether. If your blower has a fan belt, take a loot at it. If the belt is snapped, then the blower won’t work.
Why does my blower motor fail?
Rust formation inside the motor is another reason a blow motor may fail. Rust will cause a motor to seize up and prevent the motor from spinning. If your blower motor has bad bearings, damaged windings, or is otherwise seized up, then you’ll need to replace the motor.
What happens if you have bad bearings on a motor?
The bearings are the part that allows the motor shaft to spin freely. If you have bad bearings, then your motor will resist turning. Damaged motor windings are a little trickier to find. The windings are encased inside the motor, so you won’t be able to see a damaged one.
