Though having only one fan speed usually indicates a bad blower resistor, a diligent mechanic at a repair shop will test the resistor, fan switch and connections to the motor to make sure nothing else is wrong before they start replacing parts.
Why does my AC blower motor keep turning on and off?
Your AC unit turning on and off repeatedly is one of the most common AC problems homeowners face. It can be caused by dirty, damaged, failing components or electrical and mechanical factors. If your AC unit keeps turning on and off repeatedly, then it’s probably experiencing short cycling.
Why does my blower motor go on and off?
A bad brush is usually the culprit for a car blower motor turning on and off sporadically. A bad brush causes loose contact in the commutator. Either the brush is too dirty, so electric conduction is obstructed, or too worn to fit tightly in the commutator as it spins.
What are the signs of a blower motor resistor going out?
Signs of a Bad Blower Motor Resistor
- Loss of HVAC fan control (total or certain speeds)
- The fan only works on its highest speed setting.
- No air coming from vents.
- Intermittent or inconsistent fan speed.
Why does my blower motor only work on one speed? – Related Questions
How do you test a Nissan blower motor 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.
Which of the following is a common symptom of faulty blower motor?
Low/no airflow from vents.
The classic sign of a bad blower motor is restricted airflow coming from your air vents. If the blower motor is completely bad, then you’ll have no airflow at all.
How do you know if your resistor is bad?
If the resistor is fine, the multimeter will show its value in Ω, kΩ, or MΩ. However, if the resistor is bad or damaged, the multimeter may display 0 or 1. If the value 0 is displayed, the resistor is damaged, and the current can’t pass through.
Does a blower motor resistor have a fuse?
A fuse is often located on the resistor board. The fuse only protects the low and medium blower speeds. High speed will still work if the resistor fuse is blown.
How long should a blower resistor last?
The blower motor resistor is designed to last for the car’s lifespan. In most cases, these resistors will wear out long before the car does. Usually, the wear that the blower motor resistor has is due to the constant use that it gets and the heat that it is exposed on a regular basis.
Should you replace blower motor and resistor at the same time?
We do suggest that you replace the resistor at the same time. It may not be critical, but this will keep the system more uniform. The issue may even be related to the resistor. If you know that it is not related to the issue, then you do not have to replace it.
What is the life expectancy of a blower motor?
The industry standard is a 20-year life cycle. Furnace blower motors are designed and built to last many years with minor maintenance and no special attention. That doesn’t mean a blower won’t fail.
Why do I have to hit my blower motor to work?
Blower motor only start working after i hit a bump.
In most cases that is a sign of worn down blower motor brushes not making a good contact. In some cases the blower motor/resistor pigtail could cause erratic operation of the blower motor too.
What happens when a blower motor resistor fails?
Power to the blower motor is fed through the blower motor resistor, so if it fails or has any issues power can be cut off to the motor. A blower motor without power will not be able to produce any air pressure, and as a result the heating and air conditioning system will be left with no air coming from the vents.
Is it hard to replace blower resistor?
The blower motor resistor is usually extremely easy to access, but the hard part can be positioning your body inside the car to remove the part. The resistor is at the bottom of the HVAC housing or just behind the glove compartment.
What is the most common failure in a resistor?
A fixed composition resistor normally fails in an open configuration when overheated or overly stressed due to shock or vibration. Excessive humidity may cause an increase in resistance. A variable composition resistor may wear after extensive use, and worn away particles may cause high resistance short circuits.
Can you reset a blower motor?
If you have a manual reset motor overload, you’ll see a small red button on the side of your motor. This is the blower motor reset button. The red button pops out when the motor overloads. You’ll need to press the button to reset the overload and get your blower motor running again.