Air Conditioner Won’t Turn Off: Possible Reasons And Effective Solutions

“What’s wrong with my air conditioner, why won’t it turn off?” does that sound familiar? Does it feel like something you have said before? If the answer is yes then you are in the right place.

Here, I will tell you why your air conditioner won’t turn off and what you can do about it. I will try to provide you solutions for each of the problems.

But keep in mind that sometimes it will always be a better option to go for a professional servicing company. Having said that let’s get things underway.

Why Air Conditioner Keeps Running When Turned Off?

air conditioner won't turn off

Frankly, no one likes to pay the extra electricity bill. Also, a running air conditioner means a colder room temperature.

So, if your air conditioner keeps running when turned off you wouldn’t like it either. Several reasons might happen. Let’s take a look at them one by one.

  • Issues With The Contactor 

Usually, your air conditioner turns off when the contactor closes. The process is directly connected to the AC thermostat.

When you turn off the thermostat no electricity is there to power up the contactor. And the contactor is the binding force that disrupts the flow of electricity to the condenser and compressor.

However, if the contactor isn’t working fine then the air conditioner compressor won’t turn off. Even though the thermostat might turn off the compressor still keeps running.

That happens because a heated contactor can lead to several issues. Such as the contactors sticking together or getting shut in a closed state.

This means it doesn’t work well and the compressor is still running.

When the contactor can’t perform well it leads to malfunction in the condenser. The function of the contactor is to interrupt or disconnect power to the condenser.

So, failure to that keeps the condenser running hence the air conditioner keeps running as well.

  • Problematic Thermostat Wiring

You might be wondering what kind of problematic wiring your ac might have all of a sudden. Well, the problem here can be damaged wires that are used for thermostat connections. It can prevent the AC from turning on too.

Wires can easily get damaged over time. The upper layer of the wires that provide insulation can wear away. This leaves the copper wires exposed.

This leads to the constant supply of electricity through the compressor contactor. Consequently, it keeps the condenser also running. As a result, the inside ac unit won’t turn off.

Besides the decay of the insulation layer, there are some other reasons for wire damage. Such as accidentally puncturing the wires, or mice chewing on wires, or having bad quality wires.

Whatever the case may be a damaged wire can certainly lead to the issue we are discussing.

  • Malfunctioning Thermostat 

This is the most common reason why your AC won’t turn off at set tempA thermostat is a crucial part of your air conditioning system. This controls the whole temperature element of the machine.

A defective thermostat may be a cause that your ac isn’t turning off at a set temperature.

Now, if you want to determine whether it’s the thermostat or thermostat wiring you will need to do some work. First of all, you will need to check the wiring for any evident damages.

Once you think that’s fine you can easily say that there is an issue with your thermostat. But how can you say it’s not the compressor or condenser?

Well, you can do that pretty easily. Because when your thermostat doesn’t turn off due to malfunction, it will keep the condenser and compressor running anyway.

  • Clogged Ice 

Why do I say this? Well, this is a very common issue that many people sway away. Ice getting on the air conditioner is a normal thing that’s true. But clumped-up ice can cause your AC to not turn off.

Here’s how-

When there is too much ice around the evaporator coil the ac can’t reach its temperature goal. This leads to an incomplete cooling cycle so your air conditioner keeps running.

And having too much ice clumped up on that area means there is a refrigerant leak in the air conditioner.

So, these are some of the reasons that your air conditioner isn’t turning off. And don’t worry I won’t keep you hanging with the problems only. Stick with me and let’s check out the solutions to these problems.

Here is a tiny video explaining why your AC is not turning off.

What Do You Do If Your AC Won’t Turn Off?


Before we dive into this let me make things very clear for you. These are major problems for your air conditioner so in truth, there is no DIY solution for them.

In most cases, you will have to end up replacing certain parts to solve the issues. My point is don’t try to fix the problems on your own. It’s better to go for professional servicing companies.

However, if you have some technician skills then you can follow along. Let’s dive in.

  • Fixing The Contactor 

If you are facing a contactor issue then there are two solutions for this. First of all, if the contactor is damaged or broken you have to replace it.

This will require a trained technician to do the job perfectly. The cost can vary from somewhere around $120 to $350 depending on where you stay.

Another solution to this problem is suitable when the contactor is just stuck shut. In that case, you can solve the problem by yourself. You just have to use a wire brush and clean the AC contactor to unstuck them.

However, this is more of a temporary solution so you should change the contactor as soon as you can.

But hang on a minute. If you have some technical knowledge then you can do this job very cheaply. The parts may cost you from somewhere around $15 to $30. So, if you have the skills you can save a lot of money.

And you can solve the issue of your window AC compressor not turning off.

  • Fixing The Thermostat Wiring 

It’s pretty obvious once you think about it. All you have to do is fix the wiring issues. But this involves a lot of expertise with electricity.

So, it’s better to go for professional help in this case.

Hire an electrician who can connect the new wiring of your thermostat. It’s best not to try this one on your own because it requires knowledge of wiring.

However, if you choose to do it anyways make sure to take all the safety measures.

  • Fixing The Thermostat 

The solution here is simple you have to replace the thermostat you currently have. Now, this is something that requires in-depth knowledge in this field.

So, there is no alternative to hiring a professional here. And if you want to learn how to do this well that would take a lot of effort.

There is a tricky part about replacing a thermostat. You have to make a buying decision about it. You have to look for the one that matches all the criteria for your household and your air conditioner.

You can either buy it on your own or you can rely on the technician for everything.

  • Fixing The Ice-clogged Coil 

Anytime there is a problem regarding clogging, the solution is to unclog. So, here you will have to do the same. You just have to unclog the ac coils to fix the issue.

But it’s not that easy. The work requires expertise. You will need to go for professional servicing to fix the problem.

As the problem may also involve refrigerant leakage you might need to change some parts as well.

Just like I said earlier these aren’t the kind of problems that have DIY solutions. You will need some kind of prior knowledge regarding this work. Otherwise, you can worsen your air conditioner.

Here’s the deal you can avoid all that trouble with some simple preventive measure. Also, they can save you from trouble in the future. And they are very easy to follow along with.

Preventive Measures You Can Take To Avoid The Issue

ac is not cooling

Regular maintenance is the key! Otherwise, you will face the same problems like not turning on or AC keeps running but not cooling house, and so on.

Below is some measure that you can take to prevent this from of happening-

  • Get routine maintenance for your air conditioner.
  • Always clean the extra dust, ice, and debris from your air conditioner.
  • To avoid contactor issues, you can simply buy a commercial-grade contactor. They are more expensive but they can prevent this problem from happening.
  • Try to take defensive measures for your thermostat wearing. Make sure no outside force can damage them.
  • Keep up with all the parts of your air conditioner. Even the slightest malfunction has consequences that keep you alarmed.

Now get this, these aren’t something that guarantees you won’t have the issue. But they are very helpful for avoiding it in most cases.


Let’ recap. I took you through all the reasons why your air conditioner won’t turn offAnd I tried providing a solution to each of them. In such electrical appliances, it’s always best to rely on professional electricians.

Because if you mess up a single thing, it can get worse. And trust me, that is a risk you wouldn’t want to take. I hope, this was helpful for you in some way or another.

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