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Fujitsu Air Conditioner Not Turning On? Why and How To Fix It

Fujitsu is known for making great air conditioners. Unfortunately, even the best A/C units can experience problems from time to time.

Your Fujitsu air conditioner won’t turn on because the thermostat is broken, circuit breaker is tripped, condenser unit is unplugged, a fuse is blown, the air filter is clogged, the A/C drain line is clogged, the motor has failed, or there’s a refrigerant leak.

In this article, I’ll walk you through each potential cause and explain how you can identify and fix each issue. Let’s get started.

Broken Thermostat

The thermostat controls the room’s temperature, so if your air conditioner doesn’t turn on, there could be a malfunction in it.

  • Check the display. If the display is blank, it means there could be dirt inside, or someone could have turned it off. Turn it back on, and the AC will be up and running.
  • Check the batteries and replace them. This is a common reason why air conditioners stop running and also one of the most overlooked things. Pull back the thermostat cover to reveal the batteries, take out the old pair of batteries, and replace them with a new pair. Return the thermostat cover and switch it on.
  • Install the thermostat in a different location. It’s also likely that the thermostat is getting a false temperature reading. This occurs when you install the thermostat on a wall with temperature fluctuations, such as the kitchen.

If you want to find more guidelines on what to do when your air conditioner does not turn on, check out this video:

Circuit Breaker Is Tripped

A circuit breaker may trip due to power surges or overloading sockets with too many appliances. If you are using the AC and the oven and doing your laundry all at once, then it is very likely that your circuit breaker will trip. The circuit breaker protects your home from risks of fire and other electrical hazards. There are other natural causes such as storms that can cause the circuit breaker to trip.

To fix circuit breaker trips, you should check the AC switch from the control panel. Turn it to the ‘ON’ position if it was in the ‘OFF’ position.

If the circuit trips often, leave it, because it may pose a risk for fire. Call an electrician to to come and fix this kind of persistent circuit trip.

Condenser Unit Unplugged

In most AC’s the cord is connected to the panel on the side of your house. Due to exposure outside, these wires tend to weather and can be unplugged.

Unplugging limits the flow of electricity to the AC, preventing it from turning on. If your AC is a window unit, Inspect the cord coming out of your AC and plug it in correctly. If the cause is faulty wiring, call an electrician to change the wires.

Blown Fuse

The fuse box is placed on a wall outside of your house. A fuse will shut off if the electric current going through it is too high. It is advisable to turn off the AC and shut down the power to prevent electrocution risk.

Open the fuse box by lifting its metal lid. Proceed to pull out the fuses and perform a continuity test using a multimeter. If one or more fuses are damaged, buy new ones online or at a hardware store.

Clogged Air Filter

If you don’t clean your air filters regularly, they’re probably filled with dust and debris. Dirty air filters can freeze water droplets and form an icy layer on the coils, which means your A/C can’t turn on.

Before checking if the filters are clogged, turn off the A/C and the breakers, then replace the air filter.

After changing it, wait a bit for any ice to melt before turning on the air conditioner. Turning it on too soon can damage the unit.

Clogged A/C Drain Line

Without proper maintenance, your AC will be loaded with dense matter. To prevent this, always keep the condensate drain line clean. You can do this monthly by pouring a glass of boiling water down the drainpipe. Always make sure you turn off the AC and electricity while cleaning.

Motor Failure

The capacitor charges your air conditioner’s motor. If your AC is older than a decade, then the most likely cause for failure is a faulty capacitor. Having issues with the capacitor will result in your AC malfunctioning. AC capacitor failure is commonly caused by:

  • Wear and tear
  • Power surges
  • Overheated circuits
  • Short circuits in the cooling system
  • Lightning strikes
  • Extreme temperatures

To diagnose this issue, use a multimeter. Newer multimeter models measure the voltage and current, while older versions use a microammeter to mark readings. While testing your AC motor, turn off the AC and shut off its power supply.

Refrigerant Leak

The refrigerant sucks in heat from inside your home and releases it outside. The refrigerant, kept under very high pressure, circulates through your house. The cords that carry the refrigerant can erode over time, causing a leak. This leakage of refrigerant and pressure reduces the efficiency of the AC.

Indications that you’re dealing with a refrigerant leak include the following:

  • The AC was not cooling your room before, even though it was ‘ON’: The leak causes the thermostat to fail to operate and lose the ability to reach the set temperature. If your refrigerant levels are getting low, it will take longer to cool your home.
  • Your electricity bills immediately shoot up: Refrigerant leak causes your AC to work unusually. Check your electricity bills for any inconsistency.
  • Ice build-up: Ice formations on the evaporator coil are clear indications of a leak. Even though this may not cause you immediate concern, the longer-term effects could result in a complete breakdown and expensive compressor replacement. To mitigate these risks, check the evaporator coil for new ice formations.
  • The AC is leaking water: Evidence of this is finding water on your floor resulting from the melting ice in the coils.
  • Increasing levels of humidity indoors: A modern AC system cools your air and dehumidifies it at the same time. When there is a refrigerant leak in the system, that dehumidifying ability is also compromised. You may notice that your home feels clammy or damp if the humidity level is higher than usual.

If it is leaking, this is a severe issue that could lead to freon/refrigerant poisoning. You should call an HVAC professional immediately to get this fixed.


  • Vincent Steele

    Vincent is a freelance writer based in Santa Ana, California. When he isn't writing articles for Temperature Master, he can be found biking or hanging out with his cat, Shelly.

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