What does a blower fan resistor do?
By Daniel Moore
The blower motor resistor is an electrical component that is a part of the vehicle's heating and air conditioning system. It is responsible for controlling the blower motor's fan speed.
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Accordingly, how do I know if my blower motor resistor is bad?
The most common symptom of a failed blower motor resistor is when the heater fan only runs at the highest speed setting (4 or 5) and doesn't work at low speeds. In some cars, a failed blower motor resistor can cause a heater fan to stop working completely.
One may also ask, how does the stepped resistor block change the blower fan speed? The fan speed can be changed either by switching the blower resistor resistance mechanically, using a rotating lever, or electronically by the air conditioning system. The change in resistance then limits the current through the motor, which dictates the speed at which the blower fan works.
Keeping this in view, how do you troubleshoot a blower motor resistor?
How to Troubleshoot a Blower Motor Resistor
- Locate the fuse for the blower motor in the owners/service manual.
- Unplug the blower motor and test for power using the 12-volt test light in the same manner as explained in Step 1.
- Test for ground at the blower motor if there is power indicated at all ranges, but the motor does not function.
Does a blower motor resistor get hot?
Many blower motor resistors are designed such that they would burn up if they are not in the path of the air from the blower fan. They are that close to tolerance. Not because manufacturers like to burn stuff up but higher wattage resistors get very big and very expensive.. even those will get hot.
Related Question AnswersHow do you know if a resistor is bad?
Set a digital multimeter for "ohms." Set an ohms range that is equal to or higher than the value of the resistor to be tested. Touch the red lead from the meter to one side, and the black lead to the other. Resistors do not hold a polarity, so it doesn't matter which side gets the red or black lead.How much is a blower motor resistor?
Know what price you should pay to get your vehicle fixed. The average cost for a blower motor resistor replacement is between $119 and $161. Labor costs are estimated between $47 and $60 while parts are priced between $72 and $101.Where is the blower motor fuse?
Locate the fuse panel just beneath the dashboard on the driver side of the car. Remove the screw securing the fuse panel cover and remove the cover.What is a blower motor resistor?
The blower motor resistor is an electrical component that is a part of the vehicle's heating and air conditioning system. It is responsible for controlling the blower motor's fan speed. A failed blower motor resistor can cause issues with the operation of the entire heating and air conditioning system.How do you test a blower motor?
How to Test a Blower Motor- Use voltmeter or ohmmeter to check for a blown fuse. If you find one, replace it.
- Start car and see if blower motor works. If fuse blows again, check for loose circuits.
- If the circuits are in good repair but the blower motor keeps blowing fuses, replace the blower motor [source: You Fix Cars].
What happens when a blower motor resistor goes bad?
If you have faulty blower motor resistor you may experience low airflow coming from the vents even when the fan is all the way on high. In some cases bad blower motor resistor may not even turn the blower motor fan as a result your fan will not work at all and there will be no air coming from the vents.What are the signs of a bad blower motor?
Symptoms of a Bad or Failing Heater Blower Motor- Weak airflow from the vents. One of the first symptoms of a potential problem with the vehicle's heater blower motor is low airflow from the vents.
- Fan only blows at certain speeds. Another symptom of a bad or failing heater blower motor is a motor that only functions at certain speeds.
- No air from the vents.
How long does it take to replace a blower motor resistor?
about 45 minutesHow do you test a fan resistor?
Place one lead of the Ohmmeter on terminal 1 of the resistor. Place the other lead on terminal 2 and check against specifications. If this circuit is open, showing infinity on the Ohmmeter, the blower resistor must be replaced. Move the lead from terminal 2 to terminal 3 and check this reading against specifications.How do I test a resistor?
Steps- Remove power from the circuit containing the resistor.
- Isolate the resistor from the circuit.
- Inspect the resistor.
- Read the resistor value visually.
- Prepare a digital multimeter (DMM) to measure the resistor.
- Measure the resistance.
- Determine the actual resistance of the resistor.
