Every time you switch on your bath fan, you can thank Philip Diehl, a German-American mechanical engineer who developed the ceiling fan during the summer of 1889. This same technology eventually made its way, in condensed size, into bathroom vents as a way to draw moisture and odors through the venting and force it onto the exterior of a home or building.
Today’s household bath fans not only contain fan motors to draw room air through the vent, but they also often contain lighting and even heaters to quickly warm up the bathroom and help lower humidity. So what do you do if your bath fan’s light, fan, or heater aren’t working? Start troubleshooting!
Understanding how a bath fan functions
All troubleshooting begins with understanding how an appliance, a piece of equipment, or a product are supposed to work. Bath fans use 120 volts of alternating current (AC) to power the exhaust fan motor, and, if applicable, the built-in lighting fixture and heater. Usually, the exhaust fan motor, lighting, and heater are all on separate circuits controlled by individual switches, even if the toggle switches are in the same switch housing. This makes for a better user experience; after all, you don’t always need the light on when you’re using the exhaust fan and vice versa.
Exhaust fan motor
Actuating the exhaust fan switch will send those 120 volts of alternating current to the fan motor which rotates a fan blade (or blower wheel) to draw moisture or odors through its grille and exhaust it through venting positioned above the bath fan to the exterior of the home, often through a vent pipe installed on the roof.
Bath fan heater
Actuate the bath fan heater switch and the voltage is sent to an infrared heat lamp or a heating element coil. On some bath fan models, the heating element will be part of a heater assembly with its own motor and blower wheel to circulate the heated air into the bathroom.
Bath fan lighting fixture
Actuate the bath fan lighting fixture switch and the voltage will be sent to a light socket or terminal in order to power a halogen or LED light bulb, or an LED light board, depending on the bath fan model.
Why are the bath fan functions malfunctioning?
While it’s not likely that all three of these bath fan functions will fail simultaneously, the troubleshooting steps you should follow to discover why the lighting fixture, exhaust fan motor, or heater is not working can be similar:
Why the bath fan light is not turning on
Here are the three most likely causes of a bath fan light not turning on:
1) Burned-out light bulb or board – The simplest, and most likely reason, for a bath fan light not working is a burned-out or defective light bulb or light board. Replace the bulb or board to see if that resolves the problem.
2) Faulty light socket – If a new light bulb still won’t illuminate, it’s possible the light socket is faulty. If your bath fan model has a light cord that plugs into a dedicated electrical outlet inside the bath fan, you can use a multimeter to test the outlet to determine if its receiving power. You can also try plugging in another electronic device into the outlet, such as a hair dryer, to see if that device works. If the outlet is receiving power, but the new light bulb won’t work, it’s likely the socket will need to be replaced.
3) Defective light switch – A defective light switch could also be the reason the light isn’t working. As mentioned earlier, there may be three different circuits controlling the exhaust fan, light, and heater separately, depending on the bath fan model. Determine which switch is controlling the light and use a multimeter to test the switch for electrical continuity – a continuous electrical path present in the component. If the switch tests “negative” for continuity in the “on” position, then you will need to replace the old switch with a new one.
Why the exhaust fan motor is not running
If your bath fan’s exhaust fan motor won’t run, here are the top three likely reasons:
1) Incoming power supply problem – There may be a problem with the incoming power supply. This is especially true if you find more than one bath fan function (such as the exhaust fan and light) failing at the same time. Check the home’s circuit breaker box to see if a breaker has tripped or a fuse has blown.
2) Defective fan switch – If the fan motor plugs into a dedicated electrical outlet inside the bath fan, try plugging another electronic device into the outlet, or use a multimeter, to determine if the outlet is receiving voltage. If the outlet is not receiving voltage, use the multimeter to test the fan switch for electrical continuity. If the fan switch tests “negative” for continuity in the “on” position, the switch is likely at fault and should be replaced.
3) Faulty fan motor – If there doesn’t seem to be any problem with power reaching the fan motor, confirm there is nothing obstructing the fan blade or blower wheel then try turning the blade or wheel by hand. If the component does not turn freely, the bearings in the fan motor have probably seized and you will need to install a new motor to resolve the issue.
Why the bath fan heater is not heating
There are two probable causes for why your bath fan’s heater won’t heat:
1) Burned-out heating element – The most likely cause of the bath fan heater not working is a burned-out heating element. To help determine this, you can inspect the element coil for signs of damage. You can also test the coil for electrical continuity using a multimeter. If the element coil tests “negative” for continuity, you’ll know the part is defective. Since the element itself is not repairable, you will need to replace the component.
2) Faulty heater switch – Does the heating element test “positive” for continuity? Then, once again, you should use the multimeter to determine if the heater switch shows continuity as well. If the switch shows no continuity when in the “on” position, then you’ve found the culprit.
How to fix a broken bath fan
Once your troubleshooting has identified the cause of your bath fan’s malfunction, can you fix the broken bath fan yourself? Absolutely. Repair Clinic.com has videos that will take you step-by-step through replacing a damaged exhaust fan motor, burned-out heating element, faulty light bulb, and many other bath fan components. You can also get information on how to install a new bath fan motor and learn the top reasons why a bath fan isn’t venting from this blog article.
As a reminder, you’ll want to make sure you’re installing a genuine OEM replacement part to successfully fix the bath fan, one that is a direct match for your bath fan model.
Find genuine OEM bath fan parts with help from Repair Clinic
Finding the right fan motor, heating element, switch, or light bulb that matches your bath fan is essential when fixing the product or any other appliance. This is where Repair Clinic.com really shines as your repair partner. The Repair Clinic warehouse is filled with genuine OEM bath fan parts direct from the highest-profile names in the industry, including Broan, NuTone, and Panasonic. To find the correct part for your bath fan, enter the full model number of the product in the Repair Clinic website search bar to reveal a complete list of compatible parts. From there, you can use the “Part Category” filter (Examples: “Motor”, “Switch”) along with the “Part Title” filter (Examples: “Exhaust Fan Motor”, “Fan Switch”) to identify the exact component that will work with your specific bath fan.