electrician installing a fan controller wall switch

As an electrician, one of my most common call-out jobs is to repair or replace a ceiling fan switch. These 3 or 4 position rotating switches can wear out over time, especially switches that are over 20 years old.

Often I find that only one or two of the fan speed control settings works. All that has happened is the fan controller has failed in a certain position. Occasionally I find that one of the controller wires has fallen out and just needs to be wired back into position. This is a common fault due to the constant vibrations of the rotary speed controller.

Now there are many different combinations of fan controllers available. Some have light switches attached to them so there may be a few extra wires in the back of the switch. In this post, we are going to identify what each wire is, how to install a new ceiling fan speed controller and the tools needed as an electrician.

Note: Electricity is dangerous so installations and repairs must only be carried out by a licensed electrician. These tips, tricks, and instructions are for information purposes only.

Ceiling Fan not spinning fast.

There can be a number of possible reasons why your bedroom ceiling fan is not spinning so we are going to go over a few common causes.

  • Circuit breaker tripped
  • Wall switch faulty
  • Ceiling fan motor burnt out
  • Electrical wires disconnected on the wall switch or at ceiling fan terminal block.
  • Ceiling fan switch set to off.
  • Remote control batteries low.

Most of these are an easy fix apart from the ceiling fan burnt out motor where it is better and cheaper to replace the whole fan.

How to replace a ceiling fan speed control switch

isolate power at switchboard

First of all, we need to isolate the power to the fan. Often ceiling fans are powered off the lighting circuit so go to your switchboard and turn off this circuit.

Tag out the circuit breaker with a do not operate tag or place some electrical tape over the turned off circuit breaker. If you have a fuses then pull the fan power fuse out.

We now need to test that the fan circuit is dead. If the fan was working before check that it is not working. Try turning the fan on and running through a few speed control settings. Confirm with a multimeter always.

how to install ceiling fan speed control wall switch

Take a screwdriver and pull off the fan speed controller outer cover if it has one. A battery drill or a cordless screwdriver will make this job fast and quick.

Once the wires are exposed take a multi-meter and prove that the circuit has been isolated. Never work on live wires. Often fan controllers and light switches will have only switching wires going to them and no neutral or earth wires. This will make it difficult to check for voltages.

How to test for 110/240v power

A quick way to test for power at the fan controller is to turn on your multimeter and set it to read AC voltage. Now place your multimeter between the power in and the power out point. With an open connection, you should read a difference in voltage.

With the fan controller in the off state, we essentially have an open circuit so we can measure the voltage across this switch. Without the circuit isolated we would read 110v in the USA or 240v in Australia.

If you have access to earth or neutral cables, you can use your multimeter to test active to ground. Non-contact voltage testers are a great way to quickly check for an isolated circuit.

Because we have isolated the power circuit we should see 0v AC. We can now be confident in working on our isolated fan controller. You can read the following post if you would like further information on what is the voltage across an open switch.

How to install ceiling fan speed control wall switch

how to replace a ceiling fan switch

I always like to replace the same switch set up. There are basically two different types of fan controllers. Solid state which controls frequency (allowing only a portion of the current cycle to flow), and fixed speed which varies the voltage to the fan via resistance.

There are also a few variations such as light switching and dimmer control. So if you fan wall controller has a light switch as part of the set up then get the same type. Many ceiling fans have an inbuilt light. Some have a pull cord and some have a switch on the wall.

Many fan speed controllers use sliders to control the speed and lighting dimming levels. The Westinghouse 7787300 shown below is a 4 position fan controller so you have more speed control. It will turn any 3-speed overhead fan into a 4-speed fan.

In this case, we will be installing a Deka ceiling fan speed control wall switch with an included light switch. Now there are 3 wires in the wall cavity. The purpose of these wires is as follows.

  • Twin core red wire provides power into the wall switch. This provides power for both the fan and the light switch.
  • Single red core wire is switched power to the light.
  • Twin white wire is speed control power to the fan.
remove old ceiling fan control switch

The picture above shows where the fault is. You can only find this problem by removing the fan speed controller from the wall. One of the red speed control wires has come loose. As the client already wants a new fan controller we will be replacing it anyway.

Now depending on the age of your house, your wires may be different colors and different cables. They could be all single cores or they can all be twin cores. As long as you replace the same cables into the same terminals all will be good.

Install new ceiling fan speed controller

The new fan controller portion should already be wired up in the back of the switch. There will be a terminal block that should be marked power in and fan. Make sure to read the instructions that come with your fan controller to identify these terminals.

We will be using the switch for lighting to either a room light or a light on the fan itself.

3 speed ceiling fan switch wiring diagram

Below is the wiring diagram for a basic variable speed fan controller rated at 300 watts. As you can see there are only 2 wires going to the fan control unit. There is an active cable in and a switch active out to the fan.

3 speed ceiling fan switch wiring diagram

If you have more features like lighting and dimmer switches you will have more cables in the wall.

I like to remove one wire at a time for a direct replacement. This way you wont get confused on which wire goes where.

check the wiring of ceiling fan control switch and lighting circuit.

Once you have wired up your 3-speed ceiling fan and light switch it is time to screw it all back into place. I like to use the new screws that often come with the new speed controller plate.

A quick note is some people like to use smart candelabra globes in their fan lighting. This way they can turn the light on or off from a phone or a smart motion sensor. If this is the case it is ok to wire the light to an always-on position.

check all cables going into the wall fan light switch

You may have difficulties pushing in the large fan controller so be prepared to cut into the plasterboard. Sometimes the manufactures tie the terminal strip to the side of the fan control circuit and this makes it too fat to fit in. I just cut off the cable tie and secure it elsewhere.

Grab your screwdriver and screw the fan control plate back into place. Make sure it is square and level. If there is a cover plate reinstall this and place the selector knob onto the fan controller.

Energise the Circuit.

Once you are happy with your ceiling fan switch wiring you can remove your lock from the circuit breaker and energize the circuit.

Be sure to test out your new fan speed controller. Run through all the settings and also test out the light switch if you have one. If it is all good give yourself a pat on the back. If there is a fault then one of the wires may be back to front. You will have to isolate the power circuit again and test out what went wrong.

Fan motors can fail but they will either work or not. 99% of the time it is the fan controller that has failed not the fan motor. I often find that people who want a new ceiling fan is because it has noisy bearings.

Fault Finding

If after replacing the speed controller your fan may still not be turning. Please check the following

  • The power in active cable is terminated correctly.
  • Power out cable not mixed up with another cable.
  • The copper wire is terminated correctly and not crimped onto the insulation.
  • You have turned on the circuit breaker or replaced the fuse.
  • The ceiling fan is not in the off position.
  • You have selected the correct season for the year Eg: Winter or Summer mode. The fan will run the opposite direction for the different seasons.


Replacing a ceiling fan switch is a simple process that should take no more than 1/2 hour. They look complicated because there is often 3 extra wires for the speed controller. These should already be wired up into their correct position,

It is a good idea to take a picture of the old circuit for reference. Remember to always isolate your circuit and prove it with a multimeter. Non-contact power test pens are really handy items for your toolbox. Every handyman and electrician should have one.

If you have any questions let me know in the comments below.

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  1. If you have a small room or a small area, then you do not want to use a large-sized fan. Instead, you will probably want to look into small or compact wall fans that are not only efficient but also very space-efficient.


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