Simple Guide to AC Thermostat & FAQs

Do you think that your thermostat is broken? If so, then there are several things to check before calling a professional. It could be an easy fix and just as simple as flipping the switch!

You may have forgotten to change the batteries in your thermostat, or it could even be too hot or cold for the unit to work properly. Regardless of what’s wrong with it, this guide will walk you through how to find out if your AC thermostat is broken and how to fix it on your own.

What Is the Primary Function of A Thermostat In AC?

A thermostat is a very important device in an AC as it helps users control the temperature to their desired degree. It achieves this by sensing the temperature and switching the unit ON and OFF when needed to maintain the desired temperature.

Every air conditioner on the market (all types of AC) comes with some kind of thermostat, which is used to regulate the desired room temperature. Some of these thermostats are manual, while others are programmed to work automatically.

Where Is the AC Thermostat Located?

The thermostat is located behind the control panel of an indoor unit. You can access the thermostat by removing the grille and control panel. Thermostats feature a special temperature sensor that has been extended from the regulator to the evaporator coil. As the name states, the function of the sensor is to detect the temperature.

How To Identify a Bad AC Thermostat?

AC Not Turning ON

This is an obvious sign of a bad thermostat in an AC system. In fact, if the system is not turning On or failing to respond to the thermostat commends, automatically know that you have a bad thermostat.

Think of it this way, when you drive a vehicle, you are the one giving commands to that vehicle through the accelerator and the brakes. If these commands fail, the problem is often with those devices. For this reason, if your AC fails to respond to your commands, chances are the thermostat has failed.

Not Responding to Commands Or Settings

If the thermostat fails to respond to commends, there is a problem with the thermostat. The good news is that the thermostats will produce some indication when it fails. Many of them will produce a clicking sound when changes are made. If the clicking sounds don’t sound or the system does not come on shortly after the changes have been made, you need to replace your thermostat.

Why Is My Thermostat Not Working?

There are many reasons why a thermostat will fail to work.  The most common is a lack of power (like dead batteries, blown fuse, or tripped breaker). If you are certain that it is receiving power, it is wise to disconnect the power for further examination.

How To Test an AC Thermostat?

One of the ways to test your AC thermostat is by listening to the AC unit.

How do you do this? Ask a friend or family member to help you listen to the Ac unit while you are changing or adjusting the temperature on the thermostat. 

The person listening to the unit will hear whirring or clicking noises when the temperature is being adjusted. If no sound is coming from the unit, it is an indication of a faulty connection between the system and the thermostat.

Can I Replace the Thermostat by Myself?

The plain answer is YES. It is quite possible to replace a thermostat if you know how. This will save you money. However, for you to achieve this safely, you must have basic electrical knowledge, a general understanding of the type of equipment needed, and the best thermostat to get that is right for your system.

Remember, for you to take any action of repairing your AC unit, you must have at least a basic know-how of these systems and the way they work. Otherwise, you may end up damaging your unit further. Get a professional aircon repair contractor to help if you are not confident!


It is important to know how your AC thermostat works in order to be able to fix it if broken. In this detailed guide, we have explained every aspect of the system so that you can confidently troubleshoot and repair an AC thermostat yourself. If you need help with any step along the way, please contact us for assistance!

Related read: Find out more about other Air Conditioner Parts.

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