What is Car Blower Motor: Working, Parts and Signs of Failure

An air conditioning system is an essential thing to have in one’s car, especially during the summer months. That is why it is important to regularly inspect every part of the AC and have them serviced regularly. However, people often forget to examine the blower motor of a car.

This is a critical part of a car’s heating and cooling system, and a faulty motor can make a very uncomfortable driving experience. This blog aims to explain the function and importance of the blower motor and how to spot its failing signs. Read to know more!

A car blower motor is a fan attached to the car's heating and air conditioning system. There are multiple locations where you may find it, like within the dashboard, inside the engine compartment or on the opposite side of your car’s steering wheel.

A resistor in a car AC blower motor adjusts the current that passes through the motor. You can regulate its speed by changing the selected fan speed.

A blower motor resistor is used in cars which have its speed fixed to 4-5 variations. You can spot an electronic blower motor control module in cars with automatic climate control systems. This is also present in vehicles where an option to gradually adjust the speed of the blower is present.

Please scroll down to read about the functions of a blower motor and what signs you should look out for to understand its health.

The blower assists in moving the air to allow ventilation. The movement of air either flows from inside to outside or vice versa. This movement effectively transfers any heat present inside the car to the outside or the opposite side.

A blower motor resistor controls the speed of a blower. This instrument is present near the blower, right in the airflow path.

There exist two kinds of blower motor resistors. One of which incorporates coils that differ in thickness to produce resistance. Every coil present in this particular device has been assigned for each speed variation.

When you turn it to the lowest setting, the resistor consumes 12 volts to transfer 4 volts to the blower. Various coils are put to use when you attempt to increase the settings to produce higher voltage and greater speed.

Several latest models have a transistorised resistor. This resistor's functioning and location are similar to the previous type of resistor.

There are multiple ways to diagnose the blower motor of a car. Sometimes all it takes is a visual inspection to determine any existing issue. If there are no visual signs, check the resistance between terminals and compare this result to its provided specifications. In case these specifications do not match, you should replace the resistor.

After replacing your car’s resistor, if you find noises coming out of the blower motor, it means that your car’s blower motor has worn out. If you continue using it, this blower motor will restrict the resistor from working efficiently. Hence, you must also replace your car AC’s blower motor as soon as it starts to produce screeching noises when switched on.

A blower motor of a car is comprised of the following parts:

• Housing
• Motor
• Shaft
• Bearings
• Capacitor
• Belt Drives

Given are some of the warning signs of a failing blower motor:

• To test your car’s blower motor, check the voltage of the motor connector when you turn it on. If you find a voltage in your car’s motor even when it is not running, it is very likely a sign of damage.
• A fan blowing only at a certain speed can be a sign of a damaged blower motor of a car. This can happen due to a malfunctioning blower motor resistor. Hence, comprehensively check and rectify any diagnosed issues that you might come across regularly.
• Another symptom to watch out for is weak or irregular airflow from your car AC blower. With time your blower will wear out generally as the car goes through its general wear and tear process. However, this might lead to an obstruction in the general flow of air in an HVAC system. After a while, fans might stop functioning altogether, so you will want to get it serviced sooner rather than later.
• If you encounter unusual noises from your vehicle's HVAC system, take it as a sign of trouble. There is rarely any chance of a foreign element getting stuck in the engine compartment. So, any unusual sound you may be hearing is likely due to damage to the plastic blades of the blower's fans. Keep checking on your system and repair any damages as soon as you hear any slapping or popping sounds from your vent.
• Another worrying indication is signs of smoke or smell coming out while you are driving. This is another warning you need to look out for to gauge the health of your car blower motor. If you do sense anything of this sort, pull your car over and contact a nearby mechanic. Do not turn your engine back on until you figure out the reason for such an occurrence.

In the above sections, we have discussed the function and importance of the blower motor of a car AC. It is essential for bringing in fresh air and keeping the AC in working order. That is why you will want to get this part repaired or replaced if you notice any of the above-mentioned signs of damage.