Electrical

Multimeter Basics - Testing Switches

This quick tutorial shows you how to use a multimeter set to continuity mode to test both single pole and three-way switches. Learn how to identify terminals, check for proper function, and listen for that all-important tone to confirm your connections are good. Great for troubleshooting light switch issues in any home or property.
Best Practices
Diagnostic
Hard Skills
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Transcript

 And here's how you test a single pole switch and a three-way switch, a single pole switch, a standard switch you would have in any room in your house that controls a light. Make sure the multimeter is set to continuity. That's it. Okay? And one goes on each terminal. Now the switch is in the off position.

So there should be no noise. That's good. Okay. Now when I flip the switch to the on position, there's a connection. There's continuity. You should have it. Turn it off.

Nothing. Turn it on. You get a tone. Now we're gonna take a look at a three-way switch. The three-way switch has three terminals and it controls the light from two locations. It'll have a black screw, which is common, so there will always be continuity with this terminal. Now what this will do is have continuity with this side or that side.

Never, both at the same time. So I have the switch on its side. There's no tone. I have a tone. No tone. Now when I flip the switch, I should get a tone. If the switch is good.

Perfect. Now I know that that switch, these two connections are good. Now here's the other one. Terminal. So this will be uncommon.

And now I have no continuity. But if I flip the switch, I do flip the switch. I none flip the switch continuity. So that means this side is good. Same thing on this side.

When I have no continuity, I just flip the switch. Now I have continuity. That's how you test a single pole and a three-way switch.