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BLOWER MOTOR

Air conditioning in the summer and heat in the winter are both necessary for a pleasant driving experience. And without a functioning blower motor, functioning AC and heat would not be possible.

INSTALL LEVEL OF DIFFICULTY

Moderate

What Is a Blower Motor?

The HVAC (Heating, Ventilation, and Air Conditioning) system in an automobile is a very important component, as it effectively enables the driver and passengers to enjoy their motoring experience in all conditions. At the heart of the system is the blower motor, which moves the air through regulators, whether cold or hot and according to how the operator sets the climate controls.

How Does a Blower Motor Work?

The motor is usually located within the heater box, which is situated at the front of the passenger compartment, although it is possible to have two separate heater boxes (and thereby blower motors) within larger vehicles, such as an SUV. When cool air is required, the air is “blown” through the evaporator and when warm air is needed, it is pushed through the core of the heater. When activated, power is applied to the motor that will activate the fan causing it to spin, pushing large volumes of air through vents into the passenger compartment.


As temperature conditions within the car can vary so greatly, a variable speed blower motor can be controlled through a several selectors, linked to resistors and relays. When each resistor is selected, the amount of current that flows through the motor is restricted and this will govern the rotation of the blower fan. When “maximum” is selected on the dashboard, this will typically bypass all resistors and connect the fan directly to the prime source instead.

How Is a Blower Motor Made?

The motor is a simple component that consists of a metal housing that’s bolted in place for sturdy operation, a fan that sits inside the cage of the housing, a relay connected to the fan, several different resistors and the source of the power, the DC motor. The resistors are linked to the control switches situated on the dashboard and the whole circuit is connected to the vehicle’s power system through relays.

How Does a Blower Motor Fail?

  • Faulty switches, relays or resistors
  • Worn motor bearings
  • Obstructions in the fan cage causing fan failure

What Are the Symptoms of Blower Motor Failure?

  • Lack of air from the vehicle’s vents
  • Stuck on specific settings
  • Stuck at one speed

What Are the Consequences of Blower Motor Failure?

  • Overly hot or cold passenger compartment

As a vehicle’s heating and air conditioning system is in almost constant use due to American climate extremes, its components (notably the resistors) may experience a lot of wear and tear.


If you have questions or concerns about Blower Motors or any of your vehicle’s components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.