A blower motor resistor controls the speed of a car's blower fan. It's located under the dashboard, usually on the passenger side.
How it works
The resistor is connected in series with the blower motor
The resistor's resistance controls the current that runs through the blower motor
Changing the resistance limits the speed at which the blower fan operates
When high speed is selected, the resistor is bypassed, allowing maximum current through the blower motor
When it might fail
Blower motor resistors can burn out from use
They can also fail due to mechanical stresses and vibrations
Symptoms of a failing blower motor resistor
The fan usually operates at one speed only, usually the highest speed setting
Sometimes, only some of the speed settings will be faulty while others might work
What's in the box
1 x Blower resistor
