Air Conditioner Not Turning On: 10 Causes and Solutions

Is your air conditioner not turning on? Well, you are not the only one facing this problem – many people face this issue and in fact, I have faced this issue but once I found the reasons, I resolved them easily, you can do it too, once you eliminate the main reasons. But what is the reason that your air conditioner is not turning on?

In this blog post, we’ll take a look at causes why your air conditioner is not turning on, along with how to fix them, and also, how you can prevent this issue, so you don’t face this issue in future. Keep reading!

Why is my air conditioner not turning on?

Here are 10 common problems that can prevent your air conditioner from turning on.

#1 Check the circuit panel

The first thing you should do when your air conditioner is not turning on is to check the circuit panel. If a circuit breaker has tripped or a fuse has blown, the AC unit will not turn on. It’s important to check the breaker box to make sure the switch hasn’t tripped and that the fuse is still intact. 

So before doing any other steps for troubleshooting, go to your basement, garage or utility room where you have installed your electrical or circuit panel, and check that the air conditioner switch is in the “on” position. If it’s tripped, just reset it and see if the AC turns on. If it still doesn’t turn on, check the fuses. If the fuse blows, it may be due to:

  • Overloading the circuit
  • Short Circuit
  • Electrical Surge
  • Damaged wiring

If any fuses are blown, replace it and be sure to replace it with one that is rated for the same amount of amperage. After replacing it, if the problem persists, then you’ll need to call a professional to check the panel, because solving any electrical problem can be difficult if you don’t know what to do and how to do, so it will be best to call the technician.

Learn more: 

#2 Faulty thermostat

If your air conditioner won’t turn on or not blowing cold air, a faulty thermostat may be the culprit, the second most common cause after a tripped breaker or blown fuse. This is the big mama of AC units, making sure your unit is working properly. 

Check the settings and make sure the temperature is set at a level that will allow the air conditioner to turn on, switch the thermostat set to cool and set the temperature 5 degrees Fahrenheit below your room’s temperature. You may also need to adjust the fan setting or other settings in order for the air conditioner to turn on.

If the thermostat is working properly but still won’t turn on the AC, you may have a serious problem. A bad thermostat can prevent your AC from turning on, so it becomes important to test the thermostat. 

Try changing the batteries first, because most of the thermostat comes with batteries and it might be that the batteries are dead. Also, check the wiring and make sure all connections are secure. If these steps don’t fix the issue, your thermostat may have gone bad and you may need to replace the thermostat entirely.

A few signs of a bad thermostat include:

  • Inconsistent temperature
  • AC not turning on
  • Continuously running fan
  • You may also hear noises from the unit

#3 Completely blocked Filter

Do you know? Your air conditioner hates a clogged or blocked filter. Because a blocked filter prevents air from flowing through the system, and if there is no air flow then your unit can’t cool your room. 

But you may be wondering what the air filter has to do with the AC not turning on. Well, there is a strong reason. A clogged filter blocks proper air circulation, and the unit needs to work harder than usual to cool your room, and if continued for long periods of time, then there is a high possibility that any part of the unit could be damaged, and it will not start if any critical part of the unit is damaged. A dirty can also cause your ac unit to freeze up.

That said, cleaning a dirty air filter is extremely easy. To do this, you’ll need to locate the air filter compartment and remove the filter. If the filter looks very worn or if you’ve been using it for more than 3 months, you should replace it with a new one. And if it is dirty then clean it with a brush.

#4 Refrigerant leaks

Refrigerant leakage from the AC unit could be the main reason why your air conditioner is not turning on. Leaking refrigerant from an AC unit is just like bleeding from a human being. As we are all familiar with, refrigerant is a type of fluid that is used to move heat from inside the house to outside. 

If the refrigerant is leaking, it can cause your air conditioner to fail to turn on or operate at full capacity, this will have a big impact on energy bills, and it can also damage other parts of the unit, which can lead to heavy repairs. The signs of a refrigerant leak include:

  • Hissing or bubbling noises coming from the air conditioner
  • Excessive moisture around the unit
  • Frost forming on the evaporator coils or lines
  • Unusually high electric bills

Here are the steps for fixing the refrigerant leaks:

  1. Locate the source of the leak.
  2. Then repair the leak, you can do welding or brazing the leak, that’s it.

After repairing the leak, check the refrigerant level, and refill it if it’s low, you should seek the help of an HVAC professional to refill it.

#5 Blocked condenser coils

If your air conditioner is not turning on, the condenser coil could be a possible cause. These coils are responsible for transferring heat from inside your home to the atmosphere. When they become blocked or clogged with dirt, dust and debris, they cannot transfer heat properly, and over time they get worn out resulting in the air conditioner not turning on

Also, if it works too hard, the condenser will probably start to draw more power, causing problems with the electrical panel, and I have repaired many units that have problems that won’t turn on and one of the homeowners had this exact problem his condenser coils were clogged and the wires on the circuit panel were melted.

To avoid this just clean off the coils using a vacuum and brush attachment, it can take some time to clean if you are a beginner and be sure to clean it periodically to keep it working properly. I have seen that cleaning the condenser coil once a year is not so good for maximum output, I mean in a year too much dust accumulates on the coil so it would be good if you clean it twice a year.

Learn: How to clean the condenser coils?

#6 Control board issues

If you’ve checked all the other common issues and your air conditioner still won’t turn on, it may be due to a faulty control board. It is pretty much like the brain of your AC unit. The control board, sometimes referred to as the circuit board or motherboard controls the power supply and controls the various functions of the air conditioning unit.

If there is a problem with it, the unit will not turn on. To check if this is the cause of the problem, you can use a multimeter to test whether the electrical components are working properly. In some cases, the problem is minor and easily fixed with a simple trick. You can simply unplug your air conditioner from the power source and wait five minutes before plugging it back in. 

If this doesn’t fix the problem, check for corrosion, which is very common in air conditioners. Signs of corrosion could be:

  1. Rash or discoloration
  2. Metallic smell
  3. Water leaks

To fix it, apply a corrosion-inhibiting coating to the affected components. By the way, after removing the rust, if the AC still won’t turn on then you need to call a technician for help.

#7 Damaged Blower Motor

A damaged blower motor is also one of the most common reasons why an air conditioner won’t turn on. The blower motor is responsible for circulating cool air throughout your home, so when it’s damaged, it won’t be able to do its job properly, it will work harder and it’s neglected for a long time, it might be that any part of the unit is ruined and the AC will not turn on.

The most common signs of a bad blower motor are:

  • Strange noises coming from your AC unit
  • Vibrations
  • Overheating
  • Higher electricity bills due to the motor working harder than normal.

More: Signs of a damaged motor.

If you suspect that your blower motor has been damaged, it needs to be replaced. But before replacing it, I highly recommend that you call a technician to check it out, as motor replacement can be expensive.

#8 Damaged Capacitor

When an air conditioner is not turning on, a damaged capacitor may be to blame, it is a common cause. A capacitor is a device that stores and releases electrical energy, and helps the compressor of the unit to start, it also helps to start a motor. If the capacitor is damaged or has failed, it will prevent your air conditioner from turning on. 

Additional signs of a bad could be:

  • Unit running but not cooling
  • Buzzing or humming noise coming from the unit.

Causes of capacitor damaged are:

  • If the capacitor overheats, it can damage the dielectric and cause failure.
  • The surge of current can damage the capacitor and cause it to fail.
  • if the capacitor is exposed to moisture, it may short out and be damaged.
  • Running the unit for longer can cause the capacitor to fail.
  • Also, age can be a cause of a damaged capacitor.

If you find that your AC unit’s capacitor is damaged, replace it, you can do it yourself or you can even take the help of a professional, as you prefer. Anyway, here are the steps to replace the capacitor:

  1. Turn off the unit from the main electrical panel before starting the process.
  2. Locate the capacitor, it is usually located near the blower motor.
  3. Then discharge the capacitor by shorting the terminals with a screwdriver. This will free up any electrical charge stored in the capacitor.
  4. Then, disconnect the wires and remove it from its place by unscrewing it from its mount.
  5. Install the new capacitor by connecting the wires and securing it to its mount.
  6. Turn the power back on and test it to make sure it is operating properly, and you are good to go.

#9 Clogged Condensate Drain may preventing your air conditioner to turn on

Clogged Condensate Drain

Your air conditioner’s condensate drain is responsible for carrying away the condensation created by the evaporator coil. If this drain is blocked or clogged, it can cause your air conditioner to shut off completely. The most common cause of clogged condensate drains are: 

  • The buildup of dirt, dust, and other particles in the drain line
  • Blockages caused by mold growth
  • Misaligned drain pans

Luckily, unclogging a condensate drain is relatively straightforward. 

  1. First, you’ll need to locate the drain line and pay attention to any signs of blockage, which I mentioned above.
  2. If you see mildew or debris in the drain line, use a mixture of bleach and water to clean it.
  3. Then, use a vacuum to remove any remaining debris, and you are done.

#10 The outdoor unit not receiving power

If your air conditioner still won’t turn on, the power to the outdoor unit may have been turned off or may not be working properly. This can be caused by an interruption in electrical service, a tripped circuit breaker, or a blown fuse.

Check to make sure the outdoor unit has power on. If there is no power to the unit, you may need to call an electrician or your power company to diagnose and repair the problem.

How to prevent your air conditioner from not turning on? (In future)

When it comes to preventing your air conditioner from turning on, there are a few things you can do to ensure that your unit is working properly and that you do not encounter this problem again.

1)Audit your unit regularly

Audit your unit regularly to make sure everything is in good working order. This includes checking for a tripped circuit breaker or blown fuse, checking that the thermostat is working correctly, making sure the filter is not clogged or blocked, looking for damage to the capacitor, for blockage Checking condenser coils and inspecting air ducts for obstruction. If you notice any of these problems, you should take steps to resolve them immediately. 

2) Monitor the temperature

Second, keep an eye on the temperature of your air conditioner’s outdoor unit. If you notice that the unit is running very hot, it may be a sign that the refrigerant is leaking and needs to be serviced by a professional.

3) Give the unit periodic maintenance

Last but not the least, maintain the unit regularly. Believe it or not, the main indirect cause of any issues with your air conditioner is due to lack of maintenance.

Think about it, if you regularly maintain your unit, the filter will be free of dust and debris, the drain pipe will not clog, the coils will also be free of dust accumulation, and the possibility of damage to any part will be slim to low or no, that’s why it’s important that you give your unit the maintenance it needs.

You may want to consider investing in a professional AC technician to inspect and clean your unit annually. 

FAQ: Why is my air conditioner not turning on?

Here are some frequently asked questions and answers about air conditioners not starting that will help you learn more about the topic. Just have a look!

Q1. What should I do if my circuit breaker or fuse is tripped and causes my AC unit to not turn on?

Ans: If your AC unit’s circuit breaker or fuse is tripped, you should reset the circuit breaker or replace the fuse first. If the circuit breaker or fuse continues to trip or blow, this may indicate a more serious electrical problem and you should contact an electrician.

Q2. What should I check for if I suspect there are electrical problems causing my AC unit to not turn on?

Ans: If I suspect electrical problems are the reason your AC unit won’t turn on, check for loose or corroded electrical connections, and make sure they are tight and not corroded.

Q3. What can I do if the remote control is causing my AC unit to not turn on?

Ans: If the remote control is causing your AC units to not turn on then you should replace the batteries as most of the time remote causes problems due to dead batteries.

Q4. What is the most common cause for a window air conditioner not turning on?

Ans: The most common cause for a window air conditioner not turning on is tripped circuit breaker, blown fuse, or a problem with the electrical outlet.

Q5. What would make an air conditioner suddenly stop working?

Ans: Causes that will cause an air conditioner to suddenly stop working are electrical problems and dead thermostat batteries.

Wrap Up: Air Conditioner Not Turning On

Air conditioners may not turn on for many reasons, including electrical problems, thermostat problems, dirty air filters, low or leaking refrigerant, compressor problems, control board problems, blocked condenser coils, blocked air ducts and even the age of the unit is included. 

To solve the problem, check for a tripped circuit breaker or blown fuse, make sure the thermostat is set correctly and replace the batteries if dead and check and fix all the causes I mentioned above until your unit turns back on.

If the problem persists, or if you are unsure of how to troubleshoot the issue, it is best to consult a professional HVAC technician to get your unit back on again.

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David Jack

David Jack

David Jack is a veteran when it comes to air conditioners, he love helping people find solutions to their problems with AC units. His specialty is helping people find the right Air-Conditioner for their needs, whether that means replacing a broken unit or adding on to an existing system. He is also great at diagnosing problems and fixing them quickly. He learned this from my father Jack Smith who was an air conditioner repairer, he has 2 years of experience in this field.

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