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My Bathroom Fan Won’t Turn Off [FIXED]

Bathroom fans are meant to keep your bathroom dry and fight mold and mildew.

They are also meant to remove odors from your bathroom.

But what happens when a bathroom fan won’t turn off?

A constantly running bathroom fan can become an electrical or fire hazard and can permanently damage your fan.

Ignoring this issue can put the lives of your family at risk.

In this article, we will help you uncover the reasons why your bathroom fan is constantly running and how to fix this issue.

bathroom exhaust fan

4 Reasons Why Your Bathroom Exhaust Fan Will Not Turn Off

Humidity Sensors 

Some bathroom exhaust fans come equipped with humidity sensors created to fight mold.

These humidity sensors are designed to turn the fan on when the air reaches a specific humidity level.

But these humidity sensors can malfunction, causing the fan to be turned on when it does not need to be or turned on non-stop.

Another reason a humidity sensor can make your fan be on constantly is your bathroom is just exceptionally humid.


One common issue with bathroom exhaust fans running non-stop is wiring issues.

Sometimes a bathroom exhaust fan has faulty wiring or is not wired correctly.

This can lead you to discover no light switch in your home can turn your fan off.

This issue can be caused by something as simple as a loose connection or a connection not being made at all.

A bathroom fan that is running non-stop is usually not caused by the circuitry or wiring of the fan itself.

If the circuitry or wiring of the fan were malfunctioning, it is more likely that the fan would not turn on at all.

Continuous Exhaust Fans

Your fan may be running continuously because it was designed to.

Continuous exhaust fans were designed to run quietly and use less electricity.

If you are unsure whether you have a continuous exhaust fan or just a fan that’s malfunctioning, you can usually tell by the noise level of your fan and any noticeable differences on your electricity bill.

Override Controls

If you have an HVAC system installed in your home, your HVAC technician should have installed an override control.

An override control is a switch designed to be accessible to the homeowner that can shut off all fans and other aspects of the HVAC system.

For example, if the switch in your bathroom does not control the fan, then the override control is your next best option.

These master override controls are usually installed on the wall near your thermostat or in your electrical breaker panel.

This is an excellent way to turn your fan off until you can find a solution.

How to Fix a Bathroom Fan That Keeps Running

Before attempting any repairs to a bathroom fan, you must be mindful of the dangers of electricity.

If you are not a trained electrician, hiring a professional electrician to evaluate your situation would be the safest route.

Tools & Materials

  • 14 Gauge Wire
  • Crimping Tool
  • Wire Cutters
  • Needle Nose Pliers 
  • Electrical Tape
  • Screwdriver
  • Voltage Tester


Replacing the Humidity Sensor

If you are confident that the humidity sensor is your problem, possibly because it is very old, then your best option is to replace the sensor.

Different manufacturers have different sensors, but you can install one with nothing but a flathead screwdriver in most cases.

Before doing anything, ensure that the power running to your bathroom is turned off.

Then use a voltage tester to make sure it is safe.

In most cases, the humidity sensor will be a switch installed next to your bathroom’s light switch or somewhere on your bathroom wall.

  • Start by taking out the screws to remove the humidity sensor from the wall.
  • Use a screwdriver to take off the faceplate. This will expose the screws that connect to the different wires, such as the ground wire.
  • Use your screwdriver to remove these screws, and your old humidity sensor will be removed.
  • Follow the manufacturer’s directions to reconnect the wires to the proper screws, then put everything back together.

Replacing Your Fan’s Wiring

As stated previously, electrical work is best left to electricians.

But if you feel comfortable doing electrical work in your home, it is best to check your local electrician’s authority to see if you need a permit before you can begin working.

Once you have those matters cleared up, begin by turning off the power to your bathroom.

Then, use a voltage tester to ensure the area is safe to work on.

  • Check your switch box to find out the wires that go to your bathroom fan. You can use electrical tape to mark these wires.
  • Remove your bathroom fan from the ceiling, remove all cover plates, and un-attach all the wires that are connected to it. This may require you to enter the attic. Attaching tape to these wires will give you some clarity.
  • Head back to your switch box and carefully pull out all your bathroom fan’s wiring. Ensure all the wires you taped are removed.
  • Use your old wire to determine the length of wire you will need for your new 14 gauge wire. Then, cut the wire to length.
  • Feed your new wiring from your switch box to the attic.
  • Enter your attic and connect your new wiring to your fan and switch box.
  • Ensure everything is connected correctly and turn back on your power and test your new wiring.

Fixing HVAC Override Control Issues

If you’re having issues with your HVAC override control, your best option is to contact an HVAC technician.

But there is an easy way to reset your HVAC override control that may solve your problems.

  • Shut off the power to your fan.
  • Head to your circuit breaker and turn off any breakers relating to your HVAC unit.
  • Wait 30 seconds and turn everything back on.

If this does not fix your fan issue, then contacting an electrician or HVAC technician is your best option.

But this reset method is easy to do and has the potential to fix your issue.

Adam McCoy

Adam is an HVAC expert and the owner of Mackydo's HVAC Services with decades of experience in fixing and installing air conditioning units, furnaces, and every type of cooling and heating equipment you can think of.

Adam believes that your home is your sanctuary. He loves sharing advice based on his lifelong experience and treats every HVAC problem as if it was his own.

About Loo Academy

At Loo Academy, our mission is to offer trusted advice for everything related to bathrooms (design ideas, plumbing advice, showering & bathing tips, remodeling guides, and more) — a place where we all spend a great deal of time.

We work closely with qualified experts and follow a thorough editing and fact-checking process before publishing content.

Published content is regularly fact-checked and revised so that the information we provide is accurate and up-to-date.

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