The heating and air conditioning system in your car uses an electric blower motor (fan) to circulate air in the interior of the car.  Depending on the setting, the heating and air conditioning system can provide hot or cold air and/or defrost the windshield, as well as provide passengers comfort.

Heat is delivered when the blower motor blows air through the heater core and then out of the vents. The air being blown through the heater core picks up heat and the setting at which the blower control is set determines how much air is then blown from the vents.

The blower motor is usually located under the glove box area of the dashboard inside the heater housing that also contains the heater core, and flaps that divert air to the windshield, foot well area, panel vents or defroster vents.

Circuit Protection: Fuses

The blower motor is protected by a fuse if you find the blower motor is inoperative. You may need your owner’s manual or workshop manual if the fuses are not clearly labeled on the fuse box cover. If you replace a fuse, and it blows again something is causing too much current draw through the circuit. This can indicate a failing blower motor or other electrical fault.

Blower Motor Control: Blower Motor Resistor faults

The driver also controls the speed at which they want the blower motor to operate. The blower motor speed is usually controlled by a series of resistors in a blower speed module (blower motor resistor) or by a blower speed controller. If the blower motor only operates on high speed the blower motor resistor has probably failed. Again, thoroughly inspect your fuses before replacing any components. A wiring diagram will be needed to properly test the heater blower motor controls.

Air Flow: The Blower Motor

The blower motor itself is easily accessible on many vehicles being located in the passenger foot well area and can be replaced with a minimal amount of disassembly, however some manufacturers require major dash disassembly to gain access to the blower motor.

Get a free estimate for the Heater Motor replacement on your vehicle!

Clean Air: Cabin Air Filter (Dust And Pollen Filter)

If your vehicle is equipped with a cabin air filter, poor blower motor operation may be due to a partially clogged cabin air filter.

Clean Those Leaves!

The air intake for most heating and ventilation systems is the plenum tray, at the base of the front windshield. Cleaning leaves and debris from the panel beneath the windshield may also dramatically increase the efficiency of your heater blower motor. Keeping this area clean also keeps debris from falling into your heater housing. Organic plant matter inside the heater box can lead to mold and mildew buildup, which is usually the cause for the "funny [read-rotten] smell" when you turn on your heater!

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