Why Is My AC Fan Not Working? How to Fix

You get home after a long day at the office and just want to fall down on the couch. Stepping inside, it feels strangely hot inside, but you’re so exhausted that you don’t concentrate on it too much. Then, after a few hours, you realize you haven’t stopped feeling sweaty and sticky. At this point, it’s become pretty clear: your air conditioner isn’t cooling your house’s air. Importantly, the reason may be that you have an AC fan not working.
To be clear, we know how overwhelming it is to be too hot indoors without a working air conditioner fan. But don’t worry, because you’ve found the blog to help you! For the information you need, read on to learn about the roles of your AC fans, how to tell one of them isn’t working, DIY fixes for them not working, signs and causes of bad AC fans, and how to prevent future fan breakdowns.
And whether you need maintenance, an air conditioning repair, or your system replaced, SuperTech is here for Baltimore residents! Make no mistake, we have the area’s best HVAC service, so give us a call or schedule online.

I- How Your AC Fans Assist Cooling 

First off, how does your AC fan help cool your house? Well, most people aren’t aware that their air conditioners don’t actually create cold air. On that note, if you want to see the visual process of how an AC functions

Furthermore, we’ll briefly explain the process. After you set your thermostat, your house’s air is pulled into your indoor air conditioning unit through the supply vents. There, a substance called refrigerant removes the heat from your house’s air. Then, with the now-cool air returned to your home, the refrigerant is sent to your condenser so its heat can be blown outside.

The Roles Of Your Fans

In terms of the fan, you should know that there are two AC fans: one outdoors and one indoors. To differentiate, the outdoor fan is referred to as the “condenser fan” (or just the fan), while the indoor fan is called the “blower.” To that point, you may ask, “how does each one function?”

To begin, we’ll discuss the outdoor fan. To spot it, peek through the top of your condensing unit. At the top, you’ll see the fan Critically, it functions from a motor spinning its blades. Regarding its function, after the heat separates from your indoor air, it passes to the outdoor unit through copper wires. There, the condenser fan blows it outside through the condenser coil.

In contrast, the blower is inside the indoor unit under the evaporator coil. Correspondingly, it is also powered by a motor. After the system takes in the house’s air, the blower blows it over the evaporator coil to remove the heat. Once that happens, it sends the cool air into your home’s rooms.

Clearly, you can see why both fans are essential for cool indoor air flow. So, if you notice either fan not spinning, you’ll need to know why that has happened.

II- How to Tell Which AC Fan Is Not Working

There are easy ways to tell if either of your AC fans has stopped working when your house isn’t getting cold air. For one, look through the top panel guard of your condenser unit. Normally, you should see and hear the fan spinning inside. If not, the AC fan motor may have an issue. In that case, the cooling process can’t finish without hot air getting expelled outside.
Conversely, you cannot see the blower fan since it is inside the indoor unit. So, if the temperature inside your house increases, stick your hand in front of your vents and see if you feel air. If not, it’s pretty clear that the blower is not functioning. That said, take a second precaution to make sure! More clearly, go to the indoor unit and listen for if the fan is running. If it isn’t, you can be confident that either the fan or its motor has a problem.

Beyond this, if both fans are off simultaneously, that could be a more severe issue. That said, don’t fear, because we’ll get to that later.

III- DIY Fixes For Your Air Conditioning Fans

Before anything else, try these quick fixes to get your fans spinning. They may solve the issues and save you money by helping you avoid a professional repair:

1- Step One: Verify That Your House Has Power

Perhaps obviously, but if power gets cut to your house, it will shut everything down. Of course, when no electrical component in your house works, that includes both AC fans. First, wait to see if the power returns. If not, check if your house’s breaker (likely located in the basement) has tripped. Fortunately, as long as your AC system doesn’t have pre-existing issues, this should return your air conditioning system fans to normal.

2- Step Two: Turn On Your Tripped Circuit Breakers

This can affect both AC fans individually or at the same time. Frustratingly, while overall power to your house may run, individual breakers might still trip. On that note, your breaker should have  switches for the indoor and outdoor air conditioning units. To clarify, breakers may trip due to faulty AC components, excessive current flow, or surges in power. Look at your AC breakers. If they’re off, flip them back on and see if that fixes the problem.

3- Step Three: Flip Your Furnace Or Air Handler Switch On

This will directly affect only the blower, not the AC condenser fan as well. To explain, in your air conditioning system’s indoor unit, the air handler facilitates the vents pulling in and returning your house’s air. Speaking to that, the air handler has its own power switch and is linked to your heat pump or furnace. To your knowledge, those units also have power switches. When the switches for both units are off, power gets cut to your indoor unit. So, if your blower is down, you may be able to fix it by flipping the switches for both linked units back on.
Additionally, we have a blog discussing reasons why your furnace unit won’t turn on if you’d like to learn more.

4- Step Four: Check The Outdoor Unit’s Disconnect

This will only directly affect your condenser fan. Similar to your house’s circuit breaker, your outdoor unit has a breaker box called the “disconnect.” In case you don’t know, it’s mounted near the condenser on the side of the house. It includes a switch that can turn the condenser on and off. That said, if the above three fixes don’t fix your condenser fan, check if the disconnect is off.

5- Step Five: Set Your Thermostat To Cool Properly

This will affect not only both fans but the entire AC system. Most importantly, the thermostat is the AC unit’s control center, signaling the cooling process to begin after you change its temperature. Unfortunately, if your thermostat is damaged or not set properly, it may stop working. For example, a low voltage control issue could develop on the thermostat’s wire.

Therefore, if your vents are not releasing cold air or your condenser is off, double-check the thermostat settings and change its batteries. Hopefully, that will fix the issue.

Check out our blog on reasons for your thermostat not working to learn more.

6- Step Six: Put In Clean AC Filters

This will also only directly impact the blower. Critically, to protect your breathing, your AC filter snatches debris off the air as it passes through it. Problematically, an air filter can become so filled with residue over time that airflow gets blocked. In that case, reduced airflow can lead to decreased system efficiency. In turn, this could cause the blower motor to work harder to try and cool your house. As a result, the fan may overheat and shut down. Additionally, your indoor unit’s evaporator coil may freeze, shutting down your entire AC system.
On that note, keep your air filters clean. Surprisingly, a little dirt can do a lot of damage (more on this later…). Additionally, filthy filters can lead to the development of bio-growth, which may lead to your AC smelling musty.

IV- Causes Of Your AC Fans Not Running

If none of those fixes work, it’s now time to contact an AC professional for assistance. That said, continue reading if you want to learn what issues your fans might have. That way, when you hire a technician to inspect your system, you can better understand what they say about its issues.

1- Faulty Motors Not Spinning The Fan Blades

As we mentioned, the blades of the blower and condenser fans are powered by motors. The thing is, these motors can only continue running for so long and may become faulty. For example, the AC blower motor might malfunction if your filters are clogged and dirty air passes through them. Beyond this, the motors can also become less efficient if they overheat from working too hard. Additionally, avoiding maintenance can cause the same problem.

2- Loose Or Broken Belt Causes Fans To Fail

This is an issue only older AC models will face, as newer systems do not have belts. Crucially, the belt links the engines and blades of the fans. In response, the engine spins the belt to rotate the blades. However, belts can often become worn and fail, considering they are already fairly old. Most often, they will slip loose or snap. If this happens, the belt will need to be reattached or replaced before the fan can spin again.

3- Capacitor Failure Results In Outside AC Fan Not Working

The capacitor supplies the condenser’s motors with the electricity they need to function. If it fails, it cannot provide power to the outdoor unit – including, of course, the condenser fan motor. Notably, a bad capacitor can result from overheating, physical damage (due to dirt or related material), age-related wear and tear, and wiring issues. In addition, the capacitor will need to function for the condenser fan to remove heat.

4- Malfunctioning Contactor Shuts Off Condenser Fan Motor

The contactor is another switch on the condenser that supplies voltage for its components to run. However, older contactors are more prone to malfunctioning. For example, they may become dirty and fail if insects or debris coat them. Furthermore, they can fail if their coils burn due to receiving too much voltage or shaking too violently. In that case, it will cut power to the outside unit, stopping the AC condenser fan motor from running.

5- Buildup Of Dirt, Rust, Or Sludge On Condenser Fan Blades

You do not want your condenser’s fan motor caked with dirt or debris. In that situation, it may cause the motor to overheat and fail. Beyond this, the blades on a condenser fan can rust if excessive amounts of water get into the outdoor unit. Furthermore, rusting can cause refrigerant to leak from its line, keeping it from properly cooling your indoor air. Also, sludge may develop on the blades, jamming or weighing them down so that they cannot spin.
Additionally, these problems may get more severe if your system is not regularly maintained.

6- Condenser Fan Blades Get Jammed By Tree Branch

Living in a house surrounded by trees runs some risks. If you do, a thunderstorm may send a branch sailing through one of your windows. Ok, maybe it won’t be that serious. However, something more likely is a branch snapping off and falling into your condenser.
Hopefully, this will not damage your entire unit, but it may jam the fan blade. If so, the motor will overwork itself by attempting to continue spinning the fan. In turn, it could eventually overheat and break down. In addition, restrictions caused by the branch can lead to the motor becoming more damaged.

7- Heat Pump Condenser’s Defrost Control Board Shuts Off The Unit’s Fan

Because an HVAC system heats and cools, wires link the indoor unit to the condenser. To that point, some condensers function as heat pumps. If your does, it can reverse the directional flow of its refrigerant to respectively cool and heat air during the summer and winter. Equally important, these systems include a defrost control board to thaw them out if they freeze.
On that note, during the cooling process, signals from the thermostat are first sent to the heat pump’s defrost control board. So, if the control board has an issue, the AC condenser could shut down from an inability to receive the cooling signal. In effect, the condenser fan will not spin.

8- Burned Circuit Control Board Results In Indoor AC Fan Not Working

Your circuit control board could also become burnt. If so, it may be due to poor quality or improper design resulting from a manufacturing error. For example, there may be improper spacing between the control board’s switches. Furthermore, burns can result from overheating, flame exposure, and electrical surges. Regardless, if your circuit control board burns, it may cut power to the outdoor AC unit and stop the blower fan from working.

9- AC System Leak Cuts off Inside AC Fan

Your AC system can leak water for several reasons. Firstly, if the drain pan that catches condensation becomes rusted or damaged, water can spill through it. Additionally, drain lines can become clogged from buildups of dirt or debris and flood the drain pan. Furthermore, we previously mentioned that clogged filters could freeze the evaporator coil. If that happens, it can overflow the drain pans and drain lines.
In like manner, when a leak in your air conditioner is detected, several switches automatically shut it off. This, too, is a safety precaution that prevents further damage to the air conditioning unit. Of course, when the entire system shuts down, both fans will stop running.
If you want to know more about the causes of your AC leaking water, we have an entire blog on it.

V- How Can I Prevent AC Fan Breakdowns In The Future?

The best way to ensure your AC – not just its fans – stays running is to get annual maintenance before summer begins. Likewise, when SuperTech’s repair people perform AC tune-ups, they work thoroughly on the fans. For example, they ensure the secondary motor controllers are in a good range based on your system’s design. Furthermore, they check if your condenser is level and its fan blades are balanced to prevent damage to the fan motor or blades. Also, they make sure loose material – such as sticks, trash, and fabric – isn’t too close to the condenser and may get stuck inside it.

To clarify, the biggest plus to maintenance is that it keeps minor issues from worsening. Beyond this, avoiding tune-ups makes your system more likely to experience long-term problems. If that happens, you may have to pay for more expensive repairs. What’s more, even minor system inefficiency could lead to your AC burning more energy, raising your utility bills.

To help you going forward, we’ll advise you to get two HVAC tune-ups per year. Specifically, you should get one before summer for your cooling systems and another prior to winter for your heating units. Additionally, do your part to protect your condenser when it gets installed. Select a flat spot with two or more feet of space around it so exterior objects are less likely to damage it.

Cre: supertechhvac