What are the signs that blower motor repair is needed? When your heat or air conditioning stop working, your commute can get very uncomfortable very fast. Worse, in bad weather, you might not be able to see well through fogged or frosted windows.
What Is a Blower Motor?
The blower motor is an electric motor that forces air through a radiator behind the dashboard (called the heater core) to send heat through the vents. It also forces air through the air conditioning evaporator (looks similar to a radiator) to send cold air into the vents to the cabin.
These little electric motors are usually long-lived and not much of a worry. But when they break, driving can become uncomfortable or dangerous.
How To Tell If a Blower Motor Isn't Working Right
If you turn on your car's heat or A/C and get no response from the vents (no hot or cold air) and no air is being forced into the cabin through the vents (or at least, not as much as usual), then your blower motor is likely broken.
If you have two blowers (not uncommon) and you can get either A/C or heat, but not both, then the one attached to what you're not getting is the one that's broken.
What Causes a Blower Motor to Break?
The most common cause is dust or debris getting into the motor's bearings, causing them to fail. Something may also get caught in the blades of the blower's fan, causing them to cease rotating and the motor to burn itself out. Another problem could be in the electrical connection from the power source to the motor.
All of these things should be tested for before replacing the motor. Sometimes, the motor isn't broken at all, it's just an electrical connection. Other times, the motor may have burned out because of a leak dripping onto the motor, so replacement will not fix the actual problem.
Most competent DIY mechanics can probably diagnose and replace a blower motor, as most of the work involves pulling parts in order to get to the motor itself. In the case of heat, it's buried at the center of the dash, usually on the firewall. For A/C it will be inside the engine compartment, often right up against the firewall and behind the engine.