Quick Answer: How do you test a blower motor resistor with a multimeter

How do you test a blower motor resistor with a multimeter? 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.

How do I know if my blower motor resistor is bad?

What are the symptoms of a bad blower motor resistor?

  1. No Air. …
  2. High speeds only. …
  3. Low speed only. …
  4. Fan won’t turn off. …
  5. Blower motor works on some settings but not others. …
  6. Smoking vents. …
  7. Burning smell.

29 апр. 2020 г.

How do you test a blower motor with a multimeter?

Using a multimeter set on the Ohm scale, use the positive lead and test the black wire. To check the purple wire for current, use your ignition key and turn it to the run setting, turn the heater power to full power and set the multimeter to DC power. If your meter reads “no current” the motor is no good.

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How do you know if a resistor is bad?

Your meter will read it as open circuit (infinite ohms). Or maybe it’s a 0.1 ohm current sensing part. Your meter will read it as a short circuit. If it’s a larger resistor with leads and it looks and smells burnt, assume it’s bad.

Can you bypass a blower motor resistor?

In the highest speed state, the blower resistor is bypassed completely and the fan is connected directly to the car’s battery, which allows maximum current through the motor. … A blower motor resistor or a blower motor control module is the part that controls the speed of the blower motor.

What happens when blower motor resistor goes bad?

Blower motor resistor / control module problems

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.

How much does it cost to replace a blower motor resistor?

Blower Motor Resistor Replacement Cost – RepairPal Estimate. The average cost for blower motor resistor replacement is between $115 and $141. Labor costs are estimated between $47 and $59 while parts are priced between $68 and $82. This range does not include taxes and fees, and does not factor in your unique location.

How do you know if a motor is bad on a multimeter?

Check for shorts between the power wiring and ground. Select ohms resistance on the multi-meter and set for the 30,000-ohm range. Touch one lead to each motor power lead and the other to the metal motor casing. Any value less than about 0.2 mega ohms is a reason to discard the motor.

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How many ohms should a blower motor have?

Short circuits. While you may not know exactly what the resistance of your particular motor should be, know that it should be more than zero. A resistance measurement of less than 0.5 ohms usually indicates a short circuit in the motor winding.

How do you test a 12v motor with a multimeter?

Touch one of the voltmeter leads to one of the terminals on the motor and touch the other lead on the voltmeter to the other terminal on the motor. The Ohm reading should be at or near “0.” A . 05 Ohm variance is acceptable. If the meter reads “1,” then the motor has failed and needs to be replaced.

What happens when a resistor goes bad?

When a resistor fails, it either goes open (no connection) or the resistance increases. When the resistance increases, it can burn the board, or burn itself up. Modern resistors are ‘flameproof’, in the past that wasn’t always the case!

What happens if I use the wrong resistor?

If you are using such a resistor in a current-sensing application in a switch-mode circuit, you will get spurious readings or inaccurate behaviour. … For a simple LED circuit there are no bad consequences of using a resistor of higher power.

How do I know if my SMD resistor is working?

The black probe is connected to the “COM” terminal on the multimeter, and the red probe is connected to the terminal marked with an ohm symbol for resistance. Turn the multimeter dial to the resistance setting. Power off the circuit containing the resistor you wish to measure.

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Why is my blower motor not working?

In a situation where the motor doesn’t work on any speed, the most likely causes are: a blown power supply fuse, a bad motor ground connection, bad motor speed control module or a failed motor. On all systems, a failed blower motor is least likely. … Start by checking the blower fuse and HVAC controller fuse.

Can you bypass a resistor?

A wire in the left circuit is shorting the 100Ω resistor. All current will bypass the resistor and travel through the short. So typically the assumption of a short is done by redrawing the circuit. …

How do you bypass a cooling fan resistor?

The resistor just gives you the low speed fan. You can simply bypass by unplugging the two wires connected to it and connect those together. The result will be that when the low speed fan is called, you will get the full speed fan. It will not run all the time.

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