How to Replace a 4 Way Light Switch

As a homeowner, it is normal to replace an old light switch when it fails. It is also safe to hire an electrician if you don’t have wiring experience.

But have you ever tried replacing a 4-way light switch? This article will guide you on how to replace a 4-way switch.

What is a 4-way switch?

A four-way switch is a light switch that has four screw terminals and a ground terminal. It is used to control one light fixture from three or more locations.

A four-way switch works with three-way switches and must be in the middle of two three-way switches to function. 

It is a good option for large buildings where you want to control a single light from multiple locations.

Why is it important to replace a faulty 4-way switch?

Replacing an old 4 way switch is important for the following reasons.

Safety: A faulty switch can lead to electrical hazards, such as electric shock, electrical fire, and other hazards. Replacing the old switch will help safeguard the electrical system.

Convenience: A faulty 4-way switch can be frustrating to handle, it may not work fine, or be hard to flip. Replacing the switch can improve ease of use.

Energy efficiency: A faulty switch can lead to loss of current or ground faults. Replacing the switch will help save energy and also prevent electrocution due to ground faults.

Cost saving: A faulty switch can cause energy waste, leading to higher energy bills. Replacing the switch could help reduce the bill.

Required tools and materials

  • Screwdriver
  • Voltage tester
  • New 4 way switch.
  • Electrical tape

How to replace an old 4 way switch

A four-way switch usually comes with 5 terminals. Two common terminals with black screws, two traveler terminals with brass screws, and a green screw terminal.

To successfully replace the light switch, you must follow these steps:

Turn off the light source

Go to your main breaker box and locate the circuit breaker that controls the branch circuit and flip it to the off position to turn it off.

Remove the plate cover

Once you have turned off the branch breaker, move to the switch and loosen the screws holding the faceplate. Remove the plate and pull out the switch from the electrical box.

Test the circuit to make sure it is off

 To test the circuit, use your voltage tester and touch the black and red wire coming from the first 3 way switch. The tester must not show any voltage to prove that the circuit is dead.

Remove the old four way switch

Once you confirm that the circuit is dead, remove the old switch and note the wire connections. There are two ways of doing that. 

The first one is by labeling the wires with electrical tape so you don’t get confused about which wire goes where, the second one is by removing and replacing the wires one after the other.

But for this task, we shall use the second method to install the new switch.

Install the new 4-way switch

When you look at the switch, they usually come with labels such as top and bottom, or IN and OUT.

Connect the black and red wires from the first 3-way switch (power source) to the common terminals at the bottom of the four-way switch, and the two traveler wires from the second 3 way switch to the top terminals of the four-way switch.

Connect the bare ground wire to the green ground screw and tighten the screws.

Note: The white neutral wires that connect the two 3-way switches must not be tempered with.

The other way of doing this wiring is by removing one wire at a time from the old switch and attaching it to the new switch and continuously like that until you replace the switch.

Push the new wired switch into the electrical box 

Carefully push the wires and switch into the electrical box and secure it with screws. Mount the cover plate and tighten the screws to complete the connection.

Test the new switch

Once you complete the switch replacement, move on to the main breaker and turn on the light. Test the switch to make sure it is working fine. You can test it by using it to control a light.


Though it is easy to replace a faulty switch, not every homeowner can do it. If you cannot do it yourself, call an electrician. 

Because a wrongly wired switch can cause a billion dollar damage.

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About mariaelectricals

Hi, I am Emmanuel Nwankwo, a commercial electrician and the founder of I established this blog to share my decades of work experience in electrical installations and repairs.