Blower motor isn’t working

When my Yukon is sitting at and idle there is no air coming from the vents. When I'm going down the road it blows heat but not at the speed that the fan is set on. Would that be my blower motor or my resistor? Or something else?

My car has 256000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hi there. The fact that no air blows at idle but once the car moves you get flow makes it sound like the blower motor isn’t really turning at at all, but rather you have the door set to outside air. In this case, the flow at speed simply represents forced air coming from the outside.

I would first check the cabin air filter for blockage. As you have noted though, low air flow could also be due to a failing motor and/or a problem with the resistor block. Occasionally, there are issues with the blend doors and the blower wheel could be blocked with debris (if the filter is missing or perforated, then suspect debris in blower wheel).

If you are looking to have this taken care of, a certified professional from YourMechanic can come to your car’s location to diagnose the AC system and replace the blower motor and/or the blower motor resistor as necessary.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

The most common reasons a GMC Yukon ac isn`t working are a refrigerant leak, an electrical climate control issue, or a problem with the air conditioning compressor. You may not realize there`s a refrigerant leak until the air conditioner stops blowing cold.
To protect the blower motor power circuit, a 20-, 25- or 30-amp fuse is usually located in the fuse panel under the dash. The rating of the fuse will depend on the vehicle application and how much power the blower motor requires at full speed.
There can be a number of reasons why you can air conditioning is not blowing cold air. The most common reasons could be a clogged filter, cooling fan problem, radiator trouble, or it could simply be that you need to recharge (regas) your air conditioning.
Air conditioners use fuses as a way to protect the condenser from being exposed to excessive amperage. Fuses are designed to handle a limited amount of amperage based on the maximum amount that the unit is rated for: If more amperage passes through, the fuse will blow to protect the condenser from overheating.
The blower fuse is a 40 amp fuse located in the engine compartment`s fuse box.
The location of the reset button will depend on the model of your furnace, but it can typically be found on the side of the blower motor inside the blower compartment. Once you locate the reset button, press and hold it for 30 seconds. Then, release the button and wait for 30 seconds.
The blower motor relay is the electrical switch that is used to supply the power for the vehicle`s blower motor. The blower motor is the component responsible for pushing air through the vents of your vehicle`s heating and air conditioning systems.
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.
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.
Look for it first around on the exterior of your machine, especially along the bottom edge near the ground. An AC`s reset button is typically red and visible, so it should be easy to spot. If you don`t see a reset button on the outside, it could be located inside the unit behind the service panel.
Go to the home screen of your GMC IntelliLink and select `Settings`. Choose `Return to Factory Settings`. There are three options that will pop up: `Restore Vehicle Settings`, `Clear All Private Data`, or `Restore Radio Settings`. To do the reset, select `Restore Vehicle Settings`.
In short, common issues that can cause an air conditioning unit fan to stop spinning are electrical issues, problems with the capacitor, contactor issues, a burnt out air conditioner motor, a broken fan belt, or clogged air filter.
However, they can eventually burn out, so if your AC unit`s blower motor is old, it might be time for a new one. One sign of a faulty blower motor is an air conditioner that still runs without blowing cool air. Remember: If the blower motor stops working, air is not moving through the system.
1) A Bad Fuse

The most common reason why your blower motor won`t work on any speed is that you have a bad or blown a fuse. A fuse is a small wire inside of a connector that is used to protect the motor itself from a surge of electricity.

AC blows hot air

One of the first symptoms commonly associated with a fan relay is an AC that blows warm air. If the AC condenser fan relay fails, the AC condenser fan will not receive power and will not be able to cool the AC condenser.

The air conditioner fan is located in the condenser unit (the portion of the AC that is parked outside your home). Therefore, to determine whether or not this part is working, you`ll have to walk outside and look at the fan through the vents of the condenser unit.
There are three primary mechanisms which generate the pressure differences required for airflow within and through buildings (see Figure 1): wind, stack effect or buoyancy, and. mechanical air handling equipment and appliances.
The ECM Motor

In the simplest terms, an ECM motor lowers the total electrical consumption of an AC or furnace and helps to maintain proper air flow through the system.

If the fan won`t start even with a kick-start, and you hear the compressor running, you probably have a bad fan motor. This is more common with systems that are poorly maintained or that operate where a lot of dirt/debris is blown around by the wind. The only thing you can do about a bad motor is to have it replaced.
While it can differ slightly from one furnace manufacturer to the next, you can find the high limit switch by removing the furnace cabinet cover. The fan limit switch sits on a mounting plate and has a long temperature sensor that extends into the furnace plenum: an air chamber that fills with air from the blower fan.
Some air conditioning systems have a reset switch, which is a small, red button. Typically, the button will be on the outdoor unit. If you have a problem locating it on the outdoor unit, you may find relevant details on the equipment`s manufacturer`s manual. Press the red button for three seconds and release.
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.
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.
The AC compressor relay is responsible for supplying power to the AC compressor and clutch. Without this relay, the AC compressor will not have power and the AC system will not function.

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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An inconsistent starter motor that occasionally works perfectly now will not work. Then engine will not crank at all.
ANSWER : Hi there. It is possible for the starter to fail. But before replacing the starter, make sure that the battery cables are tight and clean. Then check the starter relay and make sure that the relay is clicking. If the relay is not clicking, then check for power to the relay. If there is power to the relay but there is no click, then the starter relay would need to be replaced. If there is no power to the relay, then either the wiring from the relay to the ignition switch has a break in it or the ignition switch is failing. If there is power to the relay and power to the starter motor, then the starter motor needs replaced. If you need further assistance with your no start issue, then seek out a professional, such as one from Your Mechanic, to help you.

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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.

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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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Fan blower motor not working replaced resistor and blower motor but I don’t know we’re the fuse or relay is located
ANSWER : The fuse and relay is in the power distribution center which is mounted under the hood on the left side of the engine compartment. Remove the top cover and look on the under side of the cover. You will see a diagram showing the position and name of each fuse and or relay. Keep in mind to make sure you are correctly oriented with the position of the fuse block. It can be confusing at times.

In addition to the fan motor, relay, fuse, and blower resistor, the A/C heater controls the fan speed selection. These are known to fail on Chrysler products. A scanner capable of communicating with the climate control system is necessary to diagnose this system. To avoid any unnecessary repairs, have a certified technician, like one from YourMechanic, diagnose your heating & A/C issue firsthand.

Good luck!

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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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Blower motor only works on high and wont shut off
ANSWER : Hello, thanks for writing in about your Jeep Grand Cherokee. The blower control module and connector got hot and burned from the blower motor drawing too much power. It should be replaced to fix this issue. Your A/C blower switch may also be bad or have a melted connector. I recommend replacing the blower motor before anything else is done. If you’d like to get this fixed, have a certified technician, like one from YourMechanic, diagnose the issue with your A/C and make the necessary repairs to your car.

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Burnt yellow and brown wires at blower motor resistor, is this indicator of bad resistor or bad motor? 2011 Chevrolet Malibu
ANSWER : Hi there – most likely, the problem is the blower motor resistor pack. A quick way to test this is if the blower fan still works in the "Max" position. If it does, that pretty-much rules out the motor as the problem. The resistor pack can get pretty hot while running the fan in lower settings, which could damage the wiring to it just from the heat. If the resistor shorts, increased electrical load could burn the wiring insulation as well. I would suggest an electrical inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

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