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Blower Motor Resistor

Fatima Rangwala
Well, a blower motor resistor happens to be a very important part of the cooling and heating system in a car. So with this take, imagine if it needs a replacement, it will need an immediate one!
A vehicle normally blows air through the blower, wherein, the blower motor resistor has all the controls and settings to control the air. These motor resistors are known to lessen the amount of air, which is coming through the vents. If the air is circulating on the highest setting in your vehicle, that means the device is functioning at its lowest setting thus, blowing air, which may be cool or hot, at the preferred speed in your car.

About a Blower Motor Resistor

It is a device by which an automobile's heating and air conditioning unit moderates the speed of the fan. Basically, there are two types:
  • One is the resistor wire type using different size coil of wires, with different resistances, for every fan speed.
  • And two is, a printed circuit board with fully integrated electronic circuit.
Perhaps, the worse can happen too, wherein you wouldn't get any air at all, even if the setting is kept high. This is where a car's AC problems begin, now that you can see the blower has got buggered.
You can face a situation where the motor resistor of your car when put on any setting, whether low, medium or high, simply gives the same output. That's when you would be indicated that you have to fix this problem.
Fortunately, its replacement is an extremely easy-to-do job and isn't very expensive either. Just follow some simple directions and instructions and you are good to go, doing it all by yourself.
So, moving on further, I am sure you are eager to see how the replacement procedure is carried out, that too, all by yourself! But one quickie if you aren't so highly proficient with car components location, specifically under this subject; the location must be known to you.
It is located under the dashboard on the passenger side of the vehicle. (It's easy to locate if you lie on the floorboard and look up right under the dash, the resistor is easy to spot). Also, ensure the type of motor resistor so that you can replace the correct type.

Replacement Procedure

  • Screwdriver
  • Voltmeter
  • While replacing any sort of car part, make sure you take assistance if you aren't fully acquainted with the components. If you still can't find the motor, follow the instruction manual, or take the help of a mechanic to locate it.
  • The motor is held by 2-4 small screws for a 2'' x 3'' plate. Also, there will be an electrical connector secured inside the motor with around 5-6 wires. All this certainly depends on the car's air conditioner heating control panels.
  • Well, this is the basic step to perform - before replacing, the motor resistor test must be run. In fact, it is suggested to run a test for any electronic unit which will help you determine which part is bad.
  • Now check the speed of the fan by turning the settings to all the positions. If you see no change in the working of the fan, for instance, if the setting is put on low or high and still the fan works on just one speed, you will immediately figure out the problem and switch to the next step.
  • Next step is, check for the fuses of the fan. The fuses are under the hood of the car, in the relay and fuse center. If you think the fuse looks fine, unplug it and use the voltmeter to check the voltage of the fuse. Set the voltmeter to 20 volts DC. If this still doesn't work, check for an open-circuit in the fuse.
  • Also, with the voltmeter, check the relay center if there is any power at the fuse. Two of the four terminals must show power in the center.
  • Moreover, check the voltage at the electrical connector on the motor resistor to ensure the working condition of the fuse and relay center. While doing this, see to it that there is power at the connector key and the fan is on.
  • Both the terminals must have a power supply, if only one has power, replace the resistor with a new one. And if both the terminals have power, replace the entire blower motor component itself.
  • Unscrew the resistor and unplug the connector to remove the whole component.
  • Finally, replace it by screwing and plugging the wiring connector back in the car.
Well, here were some easy-to-understand and simple-to-perform, replacement steps. Once the new component has been installed, dry run the heating and air cooling of the car on lowest setting. Do it very often, since the lowest setting extends maximum resistance to the air flow, that will pose lesser risk of a motor burn.