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Can You Bypass A Blower Motor Resistor?

The blower motor resistor is one of the most crucial components of any heating or air conditioning system. But have you ever wondered if you can bypass it? We researched this question and share the important details we learned in this post.

Yes, you can bypass a blower motor resistor. You will need to locate the resistor, detach the two wires attached to it, and connect them. If you select low-speed fans, you will obtain a full-speed fan.

Continue reading to learn more about bypassing your blower motor resistor. We will also discuss how to test and replace your blower motor resistor and the signs of a malfunctioning blower motor resistor. So keep reading.

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Can You Bypass A Blower Motor Resistor?

You absolutely can. This means that the resistor value controls the current flowing through the blower motor and its speed. The blower resistor is bypassed in high-speed mode, and the fan is directly connected to the car's battery, allowing maximum current through the motor.

Blow motor resistor

What Is A Blower Motor Resistor?

This is part of the blower motor that controls its speed. When you turn up the air conditioner's thermostat, the resistor transmits a signal to the blower motor, causing it to speed up and blow more air.

When you lower it, the opposite occurs. It is an electronic component that generates electronic pulses in response to the information you enter into the adjustment dial.

The electrical signal fluctuates, which affects the fan's overall motor speed. Electrical systems are simple, but as you can see, if the flow of electricity is interrupted, complications can arise.

What Are The Symptoms Of A Faulty Blower Motor Resistor?

The blower motor typically only operates at one speed when there is a problem with the resistor in the blower motor. Additionally, it may cause the blower motor to stop operating completely, so the vents won't be blowing air.

The following is a more thorough list of symptoms to look out for in a blower motor resistor:

Blower Motor Has One Speed

One of the most obvious signs that the blower resistor is malfunctioning is when the fan becomes stuck in one setting. The blower motor resistor controls the fan speed; hence, its inability to be changed may indicate a problem.

If the resistor fails or shorts, the blower motor may run at a specific speed. Despite the fact that you might still use the heater or air conditioner at its current rate of operation, you should repair it so that it works properly once more.

Other faulty HVAC components can also cause this symptom. Check the connections to the motor and the fan switch to ensure they are not faulty.

Certain Settings Are Not Working

A blower motor that does not perform in certain settings is another common indicator of a defective blower motor resistor.

If the internal components of the blower motor resistors break, the blower motor may malfunction or not perform at all on one or more of the settings.

A faulty blower motor switch could also cause this. Thus, a complete diagnostic is strongly recommended if you are unsure of the problem.

No Air Is Coming Out Of The Vents

When the resistor fails, no air may come out of the vents. The blower motor resistor regulates the power to the blower motor in the system. When it fails, it can cut off all power to the motor.

Air pressure cannot be produced if the blower motor is not powered. You'll be stuck with a heater or air conditioner that isn't blowing air through the vents.

If no air is flowing out of the vents, there are a few additional things you should look into before replacing the resistor. You should begin by checking the fuses. From this, you may also suspect that the blower motor has failed.

What Are The Most Common Reasons For Blower Motor Resistor Failure?

Like every other part in your car, the blower motor resistor is not designed to last forever and will need to be replaced at some point.

A defective blower motor resistor can occur due to corrosion and overheating issues.

Defective blower motor resistor, Can You Bypass A Blower Motor Resistor?

A number of car owners have stated that their blower motor resistor was damaged due to high electrical current from the rotational speed, which can raise the temperature of the blower motor resistor and harm it.

How To Perform A Blower Motor Resistor Test

To test your blower motor resistor, follow these instructions.

1. Find The Blower Motor Resistor's Fuse

Determine the location of the blower motor resistor fuse in your car. You can consult the owner's manual for your vehicle. If you don't have a copy of the handbook, you can always download it from the internet or ask a professional mechanic for help.

2. Use A Test Light

Automotive electrical test light with grey connecting wire

After locating the blower motor resistor fuse, you will need to make sure that it is operational. To do so, connect a 12-volt test light to the ground on one side and the fuse terminal on the other.

Check the power on the terminals to determine if the fuse is functioning properly. Both terminals should be powered up, indicating that the fuse is working. If they are not powered, the fuses should be replaced.

Click here to see this test light on Amazon. 

3. Unplug The Blower Motor 

Following the same procedure, unplug the blower motor and connect it to the 12-volt test light.

Testing the motor avoids the chance of misinterpretation caused by complicated electronic blower controls common in electronic temperature control systems. By sliding the blower speed switch through all locations, you may test for power at all blower speeds.

A defective resistor causes power loss at various points on the switch. At high blower speeds, the switch gives direct power to the motor.

The switch or fuse is probably malfunctioning if there is no power at a high blower speed. The blower resistor is defective if power is reported only at high blower speeds but not at low or mid-range speeds.

4. Check The Blower Motor Ground

If power is reported at all speed ranges, but the motor does not function, check for the ground at the blower motor.

Most blower motors are grounded through the case of the motor when it is put into position or through a small ground strap connecting the case to the automobile's body.

The ground connection might corrode or become loose over time, causing the motor to operate erratically.

Watch this video for more details.

How Do You Replace Your Blower Motor Resistor

The steps for replacing your faulty blower motor resistor are outlined below.

1. Locate The Blower Motor Resistor

Determine where the blower motor resistor is located. It's typically found beneath the passenger side dash or in the engine compartment. It is close to the blower motor.

2. Pull Out The Blower Motor Resistor

Car blower regulator

Disconnect the components around the blower motor resistor, including the AC pigtail and the cooling duct.

Remove the bolts holding the blower motor resistor in place with a ratchet. After the bolts are removed, the blower motor resistor can be removed. 

Click here to see this ratchet on Amazon.

3. Disconnect All The Wires

After removing the blower motor resistor, cut the wires attached to the component. Cut the wires with scissors or a wire stripper.

Click here to see this wire stripper on Amazon.

4. Install The New Blower Motor Resistor

Blow motor resistor on a gray background

Apply dielectric grease to the housing of the blower motor resistor before continuing the installation. This will keep water out, a common problem while driving off-road. Spread a coating around the plastic to form a seal that will protect the component.

Put the blower motor resistor back in its original location. Tighten the screws, connect the pigtail, and you're finished with the task.

However, there are also cases where the pigtail has already worn out. Proceed to the following step if this is the case.

Click to see this dielectric grease on Amazon. 

5. Wire The Pigtail

Disconnect the worn-out wires and reconnect the new ones. Since the cables are usually color-coded, this should be simple. Connect the new wires with the connections. Return the pigtail to its original position, and you are finished with the task.

Watch this video for more details.

Conclusion

Bypassing a blower motor resistor is a fairly easy task. You can follow the procedures in this post to test your blower motor resistor and replace one that's damaged.

If you found this post helpful, check out these related articles:

Why Does My Car Blower Motor Turn On And Off Repeatedly?

Jeep Liberty Blower Motor Not Working – What Could Be Wrong?