AC blower motor not working
The AC blower motor doesn't work. I replaced the AC On relay. The dash AC switch engages the compressor, but the blower motor does not come on.
Experienced mechanics share their insights in answering this question :
A vehicles A/C system and the vent system are two separate systems that work together. The blower is simply a fan that is controlled by the speed switch on the dash. The voltage from the switch is routed to a set of resistors that regulate the voltage. The more voltage the motor gets, the faster it goes. If the resistor pack burns out, the motor will not work. It is possible that only some of the resistors burn out. If this is the case, the blower will operate on low on some fans but not on the others. The high level usually does not go through a resistor. This means that if the blower doesn’t work on high either, it is probably not the resistors. In this case the blower might be faulty. Consider seeking help from a qualified mechanic, such as one from YourMechanic, to help you diagnose your A/C issue and suggest an appropriate repair.
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What you may be experiencing is that, when accelerating, the intake manifold vacuum is decreased. Vacuum is used to change the vents from defrost to dash to floor. With a loss of vacuum, the system defaults to the defrost position.
What Causes a Blower Motor to Go Bad? A defective ground wire or ground wire connection and an open circuit in the power-side circuit (including the fuse, wiring, and fan switch) are the most common reasons why a blower motor fails. Blower motors can also just fail from regular use due to time and mileage.
When the fan runs intermittently, it could be one of two problems. First, the motor could be overheating, which causes it to cut out. Alternatively, a loose wire, connection, or a short in the motor windings could be the culprit. Any electrical-related problems should only be addressed by a professional.
The blower motor resistor controls the power to the system`s blower motor. When it fails, it can cut off all power to the motor. When the blower motor doesn`t get power, air pressure can`t be produced. You are left with a heater or air conditioner with nothing coming out of the vents.
The blower motor resistor in your car is the part that is responsible for pushing air through the vents when using the air conditioner or heater.
One of the first symptoms of a problem with the blower motor relay is a blower motor that does not function. As the relay is the switch that supplies current to the blower motor, if it fails internally, then power may be cut off from the blower motor circuit causing the motor to no longer function.
Like other components in your HVAC system, the blower motor can wear down over time. Some of the reasons a blower motor might fail are overheating, and excessive moisture. When dust, dirt, and debris build up, it can cause the windings and bearings to burn up more quickly.
Your car`s blower motor is not only necessary for the operation of your air conditioner. Without a functioning blower motor your engine runs the risk of overheating.
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.
If little air is coming through the vents (hot or cold), then it could be because the blower motor for the fan or a switch or resistor that controls fan speed isn`t working. Another cause might be that the electronically controlled “blend doors” that direct air flow are stuck or broken.
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.
The blower resistor is connected in series with the blower fan. This means that the current running through the blower motor, and thus its speed, is controlled by the resistor value.
Many vehicles have two fuses for the blower motor, one in the interior fuse block and the other under the hood. The blower motor is usually under the dashboard on the passenger side.
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.
Dirty Air Filters
So, the furnace is triggered to stop, then it cools down only to fire back up again. This short cycling continues to repeat until the furnace receives the airflow it needs. Dirty air filters are one of the most common reasons behind furnace short cycling.
Many times this is caused by a plugged vent in the gas cap. Try running it and unscrew the fuel cap part way to see if venting the tank will allow it to run without the choke. If so, then clean the cap with hot water and dish soap or replace the cap with a new one.
These are different components. The blower motor high relay will affect high speed blower operation. The blower motor resistor will vary the lower speeds.
In a blower motor, the relay supplies the power that allows the fans to circulate warmed air. Essentially an on/off switch, the blower motor relay`s reactions start and end the heating process in HVAC systems by controlling the flow of current between the power source and the motor.
In summary, to test a resistor we need to measure its resistance value. If this resistance value we measure is equal to its actual value, then it is a good resistor. If not then it is a bad resistor.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
My car ac a year ago stopped working on settings 123 only works on 4 I did the research so I do know it is the blower motor an ha
ANSWER : In your application, there is a replaceable blower motor resistor block. The resistor block permits multi-speed operation of the fan. If some fan speed settings work, but not others, the first thing to do is test the resistor block with a volt ohmmeter. If you desire testing, and replacement, as needed, please request a blower motor/resistor block diagnostic and the responding certified mechanic will get this taken care of for you.
With regard to the A/C system, if gauge pressures (high and low) are normal when the system does operate, there are really only two principle possibilities for intermittent operation. One is circulating moisture in the system (due to a saturated dryer) which periodically freezes (and thaws) at the expansion valve and the other is a failure in the A/C control system, that is the clutch, sensors, and other electronics that control the compressor cycling. The cause of the problem can be readily found if you request an A/C system diagnostic. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
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If I get my blower motor replaced, do I also have to have my Ac recharged after replacing blower motor?
ANSWER : The blower motor on this vehicle is a simple removal and installation and does not require anything to be touched on the A/C. The refrigerant does not have to be removed. The only component that has to be removed is the glove box under cover to get to the blower motor.
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Honda Civic 2008. AC stopped working suddenly and engine check light came ON for a day.Next day AC worked and no engine light.
ANSWER : Hi there. In both cases, when an AC system is not working and a warning light is coming on the dashboard, typically a professional mechanic will complete the same initial inspection, which is to download the stored error codes that triggered the warning light initially. This tends to give them an idea as to what is causing the problems. This could be something as simple as an electrical relay that is faulty or loose or an indication of a computer related "glitch". Either way, the best way to move forward is to have a professional mobile mechanic complete a check engine light inspection.
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My AC does not always work. If I fiddle with the blower knob I can ususally get it to work on the lowest setting.
ANSWER : Hi There,
It sounds like you may have a faulty blower motor resistor. The highest speed setting may still work because in most cars in the highest fan speed settings the current bypasses the blower motor resistor. In some cars, if the resistor is failed, the fan may stop working completely. Another reason a blower motor resistor may fail is when the blower motor has a mechanical problem or when a foreign object jams the blower motor fan blade and prevents it from spinning freely. This leads to increased current through the resistor and causes it to overheat and fail. I would suggest having an expert from YourMechanic come to your location to diagnose your system to determine what may be causing the fan not to work properly.
It sounds like you may have a faulty blower motor resistor. The highest speed setting may still work because in most cars in the highest fan speed settings the current bypasses the blower motor resistor. In some cars, if the resistor is failed, the fan may stop working completely. Another reason a blower motor resistor may fail is when the blower motor has a mechanical problem or when a foreign object jams the blower motor fan blade and prevents it from spinning freely. This leads to increased current through the resistor and causes it to overheat and fail. I would suggest having an expert from YourMechanic come to your location to diagnose your system to determine what may be causing the fan not to work properly.
Read Full Q/A … : AC blower motor not working
AC blower motor not working
ANSWER : A vehicles A/C system and the vent system are two separate systems that work together. The blower is simply a fan that is controlled by the speed switch on the dash. The voltage from the switch is routed to a set of resistors that regulate the voltage. The more voltage the motor gets, the faster it goes. If the resistor pack burns out, the motor will not work. It is possible that only some of the resistors burn out. If this is the case, the blower will operate on low on some fans but not on the others. The high level usually does not go through a resistor. This means that if the blower doesn’t work on high either, it is probably not the resistors. In this case the blower might be faulty. Consider seeking help from a qualified mechanic, such as one from YourMechanic, to help you diagnose your A/C issue and suggest an appropriate repair.
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Blower Motor only working on highest speed.
ANSWER : You mentioned that you started to smell something. This may be a sign that the blower controller or the resistor was burnt out when it was hooked up wrong. You should try replacing the blower controlling resistor that you hooked up wrong. But like you mentioned, it could also be a fuse problem that has shorted. If you would like to have this looked at, have a certified technician, like one from YourMechanic inspect the wiring and determine what should be done.
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Front A/C blower motor working incorrectly.
ANSWER : One sure way to rule out the blower motor itself would be to observe voltage while the issue is happening. If the voltage being fed to the blower motor fluctuates, the problem is on the control side of the circuit and possibly the resistor. Hire one of our mobile experts to swing by and test the electrical system and track down this bug.
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2007 Nissan Altima motor mounts are new the motor vibrates a lot went the car is in drive with the ac on went I turn the ac off it
ANSWER : Hi there. It is possible that you have a vacuum leak or perhaps the transmission mounts are loose, as usually these symptoms are common with worn out motor mounts. When the AC is activated, it does create additional drag on the motor, which can make a small vibration even worse. It’s probably a good idea to have a professional mechanic come to your location and try and replicate the symptoms you are describing by completing a car is shaking or vibrating inspection.
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