Climate control dials are pictured in a car dashboard.

Signs of a Bad Blower Motor

The blower motor is an important part of your vehicle’s heat and air conditioning systems. Without it, you can’t control the temperature of your cabin — not a dire consequence, but definitely a major annoyance in extreme heat or cold. Of course, your climate control systems can fail in many ways, so it’s good to be able to identify the signs of a bad blower motor and get it taken care of without replacing a bunch of other perfectly good parts.

Getting Some Air Time

The blower motor is a small rotary motor that drives a fan sitting behind your vents, pushing hot or cold air through them at varying speeds, depending on your selection. Even though it’s in a housing, it lives in the engine compartment, so it’s not unheard of for foreign objects to get sucked into and wrapped around or caught in the fan. As the impeller blades are plastic, it’s also pretty easy for them to snap off. You might hear this as a noise coming from directly behind the vent, perhaps a light slapping, or a sudden pop before you notice a problem with airflow. Whirring noises might also result from a bad bearing in the motor. Does the noise change or increase when changing the fan speed? This is a telltale sign of a bad blower motor.

Air on the Side of CautionSigns of a Bad Blower Motor

One of the first signs of blower motor failure is weak airflow. The motor wears out over time, and can’t push as much air, leaving you wondering what happened to the air power. This also decreases the efficiency of the defroster, as it uses the same fan. You might also notice the air blowing at certain speeds, but not all of them. Or there might not be air coming out at any speed. Note that this could also be a problem with the resistor, air door actuator or a couple of other components, so get it diagnosed by a mechanic to be sure.

Blowing Smoke at You

If you ever notice smoke or a burning smell while driving, you should pull over immediately. A burned blower motor or motor wiring isn’t going to total your car, but you better be sure that’s where the smoke is coming from before continuing on the road. It’s possible to get a short circuit or burned-up motor that could produce smoke and burning smells, but get under the hood and make sure it’s not also something else. If you find a blown fuse in the blower motor circuit, that’s a clue that the circuit became overloaded. Also, with the engine off but key in, see if the smoke and smell increase when the air is set to high. If it does seem to be an electrical problem with the fan or circuit, turn the air off and take the vehicle to a qualified mechanic for repair as soon as possible.

Though generally not a safety concern, a broken blower motor can greatly reduce the comfort of your ride in hot or cold months. And seeing as they’re not terribly difficult to replace, it makes sense to get it taken care of ASAP instead of forcing yourself and your passengers to suffer though extreme temperatures.

Check out all the electrical system products available on NAPA Online or trust one of our 16,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on the signs of a bad blower motor, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photos courtesy of Blair Lampe.

about author

Blair Lampe

Blair Lampe is a New York-based professional mechanic, blogger, theater technician, and speechwriter.  In her downtime she enjoys backpacking wherever her boots will carry her, rock climbing, experimental theatre, a crisp rosé , and showering love on her 2001 Sierra truck.

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