How to Test a Light Switch with a Multimeter

Whenever you turn on your light switch, nothing seems to happen; this could be an indication that there’s a problem. The first thing worth checking for would be whether or not the bulb is well-positioned in terms of how securely it has been screwed into place with no gaps between its base & glass covers (the Globe). If these conditions seem appropriate but still none at all come up as glowing worms – meaning there must have been some sort fuse blown recently-, then potentially another source might need servicing before anything else can continue working properly.

You can test whether or not your light switch is working by using a multimeter. If you notice that nothing seems to be happening in the socket, then it may be because of an issue with either wiring and/or connections between components (bulbs).

You will need to make sure you have the right tools for running this test, and these essential items include:

  • This handy non-contact voltage tester will let you know if the switch and wires have energy before touching them.
  • In order to remove and connect the switch wires, we will require a screwdriver with both flathead bits as well as Philips head.
  • Multimeters are useful for testing a wide range of electrical properties. They can be used to measure current, resistance and even voltage! A multimeter with Ohms setting will tell you if there’s continuity in an Open or Closed circuit by showing how much power runs through it when turned on – absent this connection anything from lights switch off completely due lack energy flow through them while closures have some amount still flowing so they remain lit up nicely at all times.
  • Electrical tape

Steps to Test a light Switch using a Multimeter

Switch off the Power

If the design of your house is old-fashioned, you will need to use a fuse panel and remove it from its socket. This needs doing because there are no breaks in electricity when multiple circuits exist within one switchboard – this means if anything goes wrong with any individual section then we can still turn off all else by shutting down these fuses first.

Test for any power on the light switch

The first thing you need to do is remove the screws that are usually placed on the over switch cover plate so your wires can be exposed. However, before handling any of them make sure to test every wire inside the electrical box with a non contact voltage tester and also remember not to miss test side terminals if there is electricity running through it because this may cause an accident while working in close proximity to the power source.

There’s one more important step: “In case any present”, run tests again just for assurance purposes that there is without a doubt no voltage.

Identify the type of switch

The first step in identifying the type of light switch is to remove screws from each side and take out any labeled pieces. A single-pole Switch has only one terminal, so you’ll need an extra pair for this kind! If there are two sides with labels on them then it’s probably a polearity limiter or protective device which can prevent damage if someone touches both wires at once when removing their own panel – just leave these intact but mark down where they go beforehand because we’re going into detail about what goes where later down below…

Whether you count the green screws or not is entirely up to your preference, but be aware that there may only be one.

The ground wire connects directly onto these colored fasteners at either top and bottom positions on a light switch’s module (where it meets with copper).

To find which terminal is for power in the switch, you will have to look at its third mounted pole. This dark colored metal tab usually has an edge that can cut through tape and reveal where wires go into it with electrical marks along their lengths; these are your connections when installing new components so make sure not only do they match up but also stripped ends meet properly before applying force onto anything else.

Take out the light switch

Once you have loosened both the screw as well as ground terminals, pull every wire from its respective terminal. After this is done take back your light switch so that it can be tested on a work surface where further examination may occur if needed.

Testing the switch for the continuity

Single-pole switch: With your multimeter, test the continuity of each screw terminal by touching it with one tester probe. You should get a near-zero reading when all switches are turned off or “1” if there is no connection at any point during the assembly process.

Three-way switch: When using a multimeter, you should touch the tester probe to each terminal in turn and then switch off. The reading will be “1” if there is electricity flowing through it from the dark colored side (or whatever) towards white ones but zero when going backwards so make sure your leads are not reversed before moving onto the next step.

Replacing or Reconnecting the Switch

When you are done, make sure to connect your switch and tighten both terminals. If replacing an old one, use a new one that has the same amperage rating as what was there before for proper operation- this will ensure nothing happens when switching out older components with newer ones.

Finalize the job

When you are done with your work, put the light switch back in place and then carefully replace wires onto a box as well using mounting screws to keep it safe. Moreover, fix the cover plate before switching off power from either fuse or breaker at test-time if necessary.


With this article, you now have the knowledge to test any light switch with a multimeter. With step-by-step instructions on how to do so quickly and correctly next time an issue arises – knowing what exactly is wrong will be easier than ever before.

The multimeter is an essential tool to have around the house. It can be used for so many things and will always come in handy when something goes wrong with your electronic devices.