How to Troubleshoot Three-Way Switches

  • Turn off power to the switches at the circuit breaker and using a tester, make sure power is off. …
  • Using a continuity tester, check continuity between the common (black) terminal and each of the traveler terminals (brass colored) of each 3-way switch.

How do you troubleshoot a 3-way switch?


Quote from Youtube video: We have two wires that go down into this box they both have a white and a bare ground wire. Now this one has a black wire that goes up to the light fixture.

What happens if 3-way switch is wired wrong?





If you don’t correctly connect this wire, then your lights won’t work from more than one switch. Grounding the switch: You’ll also need to locate the ground wire and connect it to the switch too.

What causes a three-way switch to go bad?

The wiring down wind from the switches to the lights may have open circuited. You may have wiring that was done with quick connect poke in installation. These are prone to failure more often than one cares to think. Maybe there was an electrical surge that happened to take out all of the lights at once.

Why is my 3-way light not working?

3-Way Bulbs



With a 3-way bulb, if it isn’t working at all, it’s probably dead. You can test it by moving it to a working 3-way socket, but it’s very rare that both elements of a 3-way bulb will fail at the same time. But if part of it is coming on and the other part isn’t, the problem may be with the socket.

Which wire is always hot on a 3-way switch?

Black wire





Black wire: This is a hot wire that carries electricity from the power source to the first switch in a typical 3-way setup. It’s also called the “common wire” or the “line wire.” Unless the breaker is off, this black wire is always hot.

How can I tell which wire is hot on a 3-way switch?

Quote from the video:
Quote from Youtube video: If no house current is found on any of the three wires. Go to the other switch. And do the same thing one of the wires will have house current and that wire is the hot wire mark.

How do you troubleshoot a 3-way wire?

How to Troubleshoot a Three-Way Switch

  1. Toggle the first switch. Turn the light on.
  2. Toggle the second switch. If you can turn the light on and off with this switch, this means that the switch is working. …
  3. Now go back to the first switch. Turn it on and off.


Why does my light stay on when the switch is off?



The most likely error is that the wire going to the light that stays on is contacting one of the live wires. To check, disconnect all the wires from each other, turn on the breaker and use a voltage tester to identify the live circuit wire.

Why does my light switch not work sometimes?

Fuse burnout and tripped circuit breakers can contribute to light switch malfunctioning, too. Because of this, it’s important to take a look at your circuit breaker before you go ahead and buy a whole new light switch. Sometimes, you can replace a fuse and correct the situation.

How do you test a 3-way switch?

Quote from the video:
Quote from Youtube video: Now we move the switch to the top position you can hear the tone. And you can see the meter. Is going to all zeros. Here. We have a good connection on this side of the switch.

How do you check a light switch to see if it is bad?



Turn the switch lever on and off. The tester should light up when the switch lever is in the on position but should not light up when the switch lever is off. If it doesn’t exhibit this behavior, it indicates the inner connections are bad and that the switch needs to be replaced.

What happens if a light switch is wired wrong?

But here’s the catch: If you connect the circuit wires to the wrong terminals on an outlet, the outlet will still work, but the polarity will be backward. When this happens, a lamp, for example, will have its bulb socket sleeve energized rather than the little tab inside the socket.

What color wire goes to the black screw on a 3-way switch?

Tighten the terminal screws. Connect the ground wire to the green screw, then connect the wire marked common to the black or dark colored screw. Connect the two remaining traveler wires to the two brass or light colored screws.

Where does the red wire go on a 3-way switch?

The black hot wire connects to the far right switch’s common terminal. Red and blue wires link traveler terminals of both switches. The red wire, which is connected to the first switch’s common terminal, leads back to the fixture.

What is the line side of a 3-way switch?



In a 3-way configuration, the “Line” wire should be connected to the “Common” terminal of the Brilliant Control. Load Wire: This is the wire that connects your switch to your light bulb or other “load” (ie: a fan or other appliance). It is also usually black.

How do you tell which is load and which is line?

The line side of an outlet is where you connect the incoming source power. The load side is where the power leaves the device (or electrical box) and travels down the circuit.

How many wires are needed between 3-way switches?

three wires

With a three-way switch, three wires connect the pair of switches—two black “traveler” wires and a third “common” wire. When the circuit’s power is turned on, any of these may be “hot,” depending upon how the switches are toggled.

How can you tell which wire is hot and load?



Quote from the video:
Quote from Youtube video: And then remember gold goes to the hot. Side so the gold terminal. And that's on my line. Set and then silver goes to neutral or the white wire.

Why are there 2 black wires on light switch?

Black means hot, white signifies neutral, and green indicates ground. However, if you need to rewire a light switch or a plug socket, you may occasionally come across two black wires. It’s essential that you determine which black wire is hot before proceeding.

Which wire is hot when both are black?

Here’s a rundown of electrical wires: The black wire is the “hot” wire, it carries the electricity from the breaker panel into the switch or light source. The white wire is the “neutral” wire, it takes any unused electricity and current and sends it back to the breaker panel.