How does a blower motor resistor control the fan speed?

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.

Can a broken motor switch stop a blower?

A broken blower motor switch can also stop the blower from changing to certain speed settings. If your blower motor cannot change to certain speeds, check both the resistor and the switch on your dashboard. The most common failure points are the resistor and the motor itself.

How does a relay work on a blower motor?

Finally, with the fan switch on the highest speed, the fan motor is receiving system voltage (14.5 with the engine running). Some systems will energize a relay when the switch is set at the highest fan speed. The relay then closes its contacts, feeding full voltage to the fan, because a relay can handle the current better than the fan switch.

What are the symptoms of a failed blower motor resistor?

Blower motor resistor problems. Problems with a blower motor resistor are common in many cars. The most common symptom of a failed blower motor resistor is when the heater fan only runs at high speed and doesn’t work at low speeds.

Is my blower motor bad?

No air from the vents. No air flow from the vents when the heater or air conditioning is activated is another symptom of a bad blower motor. If the heater blower motor burns out or short circuits, it will not function, and therefore will not be able to produce any airflow for the system. The blower motor will usually have to be replaced in order…

What is the purpose of a blower motor resistor?

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. A failed blower motor resistor can cause issues with the operation of the entire heating and air conditioning system.

Where is the resistor for the blower motor located?

Two individual resistors make up the blower motor resistor assembly on your Chevy pickup. As you’re probably already aware, these resistors are located between the A/C-Heater control panel and the blower motor . The purpose of these resistors is to reduce the amount of the blower motor’s current that’s passing through them.

Is there a relay on the blower motor?

The blower motor relay is the electrical switch that is used to supply the power for the vehicle’s blower motor . The blower motor is the component responsible for pushing air through the vents of your vehicle’s heating and air conditioning systems.

How can I change the speed of my blower fan?

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. The change in resistance then limits the current through the motor, which dictates the speed at which the blower fan works.

Which is the best brand of blower motor resistors?

Autozone is the one-stop shop for the lowest prices on blower motor resistors. We stock all of the biggest and best brands, including Duralast, Santech and 4Seasons.

How much does it cost to replace a blower motor resistor?

The blower motor resistor or control module replacement is not very expensive. For example, one of our colleagues had a problem with his 2011 Ford Escape: the fan only worked at the speed 4. He paid $50 to diagnose and $112 to replace the resistor at a local Ford dealership.

What to do if your blower resistor Burns?

Look for obvious signs of corrosion and burns from overheating. If you see signs of overheated connectors, replace the blower resistor and its connector, but again, you must splice the wires right, or you’ll have problems at the splice later on.

How much does a blower motor resistor cost?

Depending on the manufacturer and model, a blower motor resistor can go anywhere between $3 and $335 on CarParts.com. The replacement parts come in individual units, sets of two resistors, or as part of a blower motor resistor kit.

What happens if the blower motor only works on high speed?

In other designs, the failure of 1 resistor means you lose only one speed. However, most car makers bypass the blower motor resistor completely when you move the fan speed switch to high. If your blower only operates on its highest speed, chances are you have the series type of blower motor resistor. This is the most common failure mode.

What causes a blower fan to not work?

When this happens, you may notice that you will not feel anything blowing out of the vents at all. This may also cause the blower motor to work intermittently. A blower fan is connected to the negative battery terminal (also called ground) on one end and to the positive battery terminal through a blower motor resistor on the other end.

Why does blower motor resistor keep going out?

The blower motor appears to be defective here. When the brushes wear out the motor draws excessive amps which could cause the resistor to burn out. Before making further replacements remove the motor and check it, especially the brush assembly. This is the most likely reason for the resistor to fail repetitively.

What does blower motor resistor do?

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. When fan speed is changed via the knob on the instrument cluster, the blower motor resistor changes setting, which changes the speed of the blower motor.

What is the function of blower motors?

What Does a Blower Motor Resistor Do? Definition. A blower motor resistor, typically located beneath the passenger side dashboard, contains three resistors, or sets of terminals designed to generate voltage in proportion to electrical current. Function. Blower motor resistors contain controls that determine air settings. Repair.

What causes a cooling fan resistor to stop working?

There are several reasons that a cooling fan can stop working and a cooling fan resistor is just one possibility. If the engine is overheating or the cooling fan does not operated at all possible speeds, there may be an issue with the resistor. If the resistor is broken, the cooling fan may never turn off.

Where is the fan resistor on a radiator?

Step 1: Locate the cooling fan resistor. Visually inspect the area on and around the radiator cooling fan assembly. While most manufacturers mount the cooling fan resistor directly to the cooling fan assembly, not all do.

What happens when a cooling fan resistor fails?

The cooling fan resistor is meant to send power to the fans in steps, so that the fans may operate at different speeds. If any of the individual steps or switches fail, it will disable the cooling fans from operating on that speed setting. You may notice that the cooling fans only operate at one speed, when they used to operate on two or more. 3.

Why does my AC fan only work on high?

Your AC only working on high probably has to do with the blower motor resistor. It controls the speed of your fan and if it brakes it will only work on high. Try replacing that resistor first to see if you regain control of the fan speeds.

How does a blower motor resistor control the fan speed?