Blower motor resistor / control module problems 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 happens when a 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.
Can blower motor cause overheating?
A blower motor overheats when the furnace is able to turn on but it isn't functioning properly. This means the blower motor is working but it's not distributing any hot air, thus causing it to overheat. The excessive heat that is produced stays within the blower motor itself and can lead to costly damage.
Does blower motor affect temperature?
The blower motor is an important part of your vehicle's heat and air conditioning systems. Without it, you can't control the temperature of your cabin — not a dire consequence, but definitely a major annoyance in extreme heat or cold.
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.
What happens when a 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.
What are the signs of a blower motor resistor going out?
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 makes a blower motor go bad?
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.
Does thermostat control blower motor?
The fan setting on your thermostat controls your HVAC's system blower. The blower helps circulate hot or cold air throughout your home until the temperature on the thermostat is reached. There are two settings on your thermostat to control the fan – auto or on.
How do you test a fan 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.
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.
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 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 do I 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 much does it cost to replace a blower 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 a bad blower motor resistor cause no AC?
No Air Coming From 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.
What happens when a 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 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.
What does the heater blower motor resistor do?
The blower motor resistor in your car is the part that is responsible for pushing air through the vents when using the air conditioner or heater. The blower motor resistor is constantly put under stress which can cause it to eventually fail.
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.
How hard is it to replace a blower resistor?
How to Replace a Blower Motor Resistor. The blower motor resistor is usually extremely easy to access, but the hard part can be positioning your body inside the car to remove the part. The resistor is at the bottom of the HVAC housing or just behind the glove compartment.
Can you drive without a blower motor?
Your car's blower motor is not only necessary for the operation of your air conditioner. Without a functioning blower motor your engine runs the risk of overheating.
How do I reset my AC blower?
Locate the reset button on the furnace and press it to reset the furnace. It is usually located inside the blower compartment on the side of the blower motor. Be cautious as the housing may be hot. If the button is popped up, press it down.
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.
Does AC and heat use same blower?
Similarly, your home's heating and air conditioning units form another complex system and share critical components. These critical components are your furnace and air conditioner. They often use the same blower to force conditioned air throughout your home.
What happens when a blower motor resistor is too hot?
Excessive current can overheat and permanently damage the blower motor resistor In this case, the heater and air conditioning system may still function normally pushing the cold or hot air out of the vent beside the speed. The resistor needs to be replaced with a new one in order to restore its function.
What causes a fan motor resistor to go bad?
Yes, the most common reason for the fan motor resistance to become bad is that the blower motor rotates slowly or heavily, which will create a lot of heat in the resistor and the internal fuse will blow. In most cases, if you don’t replace the fan motor at the same time – the resistor will go bad again shortly after.
Is the heater blower motor resistor expensive to replace?
In the scheme of air conditioning and heater parts, this is one of the least expensive to replace. The heater blower motor resistor can often go bad because of a bad heater fan, and therefore you often have to replace both the heater blower resistor and the fan. It’s also not a difficult part to replace.
Does a blower motor need a resistor pack?
If a blower motor does not use a resistor pack to control speed, it uses a control module. The module contains the electronics to regulate speed based on sensor signals. Just like the resistors, it’s also prone to damage by overheating and corrosion and leads to bad blower motor symptoms.
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