Troubleshooting Guide: When Your Air Conditioner Won’t Turn On

Has your air conditioner suddenly stopped working despite hearing the thermostat click? It can be frustrating and uncomfortable, especially during hot summer days. Several factors could be causing this issue, ranging from simple fixes to more complex problems. In this guide, we’ll walk you through the steps to diagnose and potentially resolve the issue thermostat clicks but air conditioning won’t turn on after you hear the thermostat click.

Check the Thermostat Settings

The first step in troubleshooting an air conditioner won’t turn on is to check the thermostat settings. Ensure that it’s set to “Cool” mode and that the temperature setting is lower than the current room temperature. Sometimes, incorrect settings can prevent the air conditioner from starting even though you hear the thermostat click.

Inspect the Circuit Breaker

A tripped circuit breaker is a common reason why an air conditioner won’t start. Head to your electrical panel and check if the breaker connected to your HVAC system has tripped. If it’s in the “off” position, reset it by turning it fully to the “on” position. This simple action may restore power to your air conditioner.

Examine the Air Filter

A clogged air filter can restrict airflow to your air conditioner, causing it to overheat and shut down as a safety measure. Inspect the air filter and replace it if it’s dirty or clogged. A clean filter ensures proper airflow and can prevent many common HVAC problems.

Look at the Condensate Drain

If the condensate drain becomes clogged, it can trigger a safety feature that prevents the air conditioner from turning on. Check the drain for any blockages and clear them if necessary. Ensuring proper drainage can resolve this issue and allow your air conditioner to operate normally.

Inspect the Outdoor Unit

Head outside and inspect the outdoor unit of your air conditioner. Ensure that there are no visible obstructions such as debris, overgrown plants, or branches that could be blocking airflow or causing damage to the unit. Clear away any debris and ensure a clear space around the unit for optimal operation.

Check the Capacitor

The capacitor is a component that helps start the compressor and fan motors in your air conditioner. A faulty capacitor can prevent the unit from starting despite the thermostat click. Capacitors can sometimes bulge or leak, indicating they need replacement. A professional HVAC technician can test and replace the capacitor if necessary.

Test the Contactors

Contactor relays are responsible for supplying power to the compressor and fan motors when signaled by the thermostat. If the contactors are worn out or damaged, they may not engage properly, preventing the air conditioner from turning on. A visual inspection can sometimes reveal burnt or pitted contacts, indicating a need for replacement.

Call a Professional Technician

If you’ve checked all the above components and your air conditioner still won’t turn on after the thermostat clicks, it’s time to call a licensed HVAC technician. They have the expertise and tools to diagnose more complex issues such as compressor failures, refrigerant leaks, or electrical problems that require specialized knowledge and equipment to repair.


In conclusion, troubleshooting an air conditioner that won’t turn on after the thermostat clicks involves checking several key components. From thermostat settings to electrical issues and mechanical components, each part plays a crucial role in the proper functioning of your HVAC system. By following the steps outlined in this guide, you can often identify and resolve the issue yourself. Remember, for more complex problems or if you’re unsure about performing any checks, it’s always best to contact a professional HVAC technician to ensure your system is repaired safely and efficiently.

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