The thermostat control uses a sensor bulb to monitor room air temperature which in turn operates a set of enclosed electrical contacts to supply power to the compressor circuit. But hopefully, this article on troubleshooting when your AC won't turn on was helpful at getting you to where you need to be. There are many reasons an air conditioning unit may automatically switch itself on and off. The most common causes of this problem tend to be the build up of dirt on the compressor or condenser, faults with the thermostat or timer, or issues with the circuit board. When your air conditioner won't turn on, it can be frustrating and uncomfortable. A Dead HVAC Compressor. A compressor that shakes or stutters when it’s turned on, otherwise known as hard starting. warm or hot air is blown into the house). When the compressor is not coming on, your air conditioner unit will not run properly. An air conditioner that has lost its cooling capabilities or is cooling inadequately (i.e. In most cases, the problem is usually simple enough for a DIY quick fix, but there are instances when an HVAC technician may be required. There are a lot of factors that determine whether your compressor will turn on, including blockages and problems with the thermostat that may prevent the compressor from working properly. ... Read More. An AC compressor that won’t turn on. If your air conditioner has a rotary type temperature control or thermostat and does not turn on you may have a defective control. Fun fact: Your AC probably needs up to 3 times the amount of power at start-up than it uses to run. Required Part. Final Thoughts on When Your Air Conditioner Won't Turn On. When turning on the AC, you may notice the fan running when the compressor is not. Panasonic Air conditioner compressor won't run. If not, then it's time to call in a pro. We can help you find your model number right away. To find just the right part, enter your model number. Your capacitor is housed inside your outdoor unit and acts like a giant battery that gives your AC compressor the extra voltage it needs to start up. If the replacements do not bring your HVAC compressor back to life, you have two options. Summary aircon can automatically turn on and off. AC capacitor sits inside the outdoor unit. It is possible for the thermostat to still turn on the fan motor but not the compressor motor. You may have a technician replace your compressor, or you may decide to replace the entire air conditioning system altogether.