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How to tell if a light switch is bad

Flipping a light switch is something we all take for granted. For the most part, it just always works. But as a homeowner, you may find that you’ve just walked into a room, flicked the light switch, and something’s not right. While this might be annoying –who wants to walk around in the dark? —the good news is, many causes of faulty light switches are common and can be easily diagnosed.

Shedding light on common problems

One common issue is a problem with the switch’s resistance; it may be too soft to flip—or even too rigid. Sometimes, the switch might have to be jiggled to stay on. (In this case, this might indicate the switch mechanism is worn and needs replaced.) Another common problem might be a light switch making an unusual noise. This could be caused by loose wire connections. More likely, these sounds are warning signs of a worn or defective switch that needs to be replaced.

Sometimes, you might see a small spark coming from inside a switch when you turn it off. As worrisome as it may look, in most cases this isn’t cause for alarm; it’s simply a signal that the electricity is jumping between contacts as they pull away from each other. However, a large spark or a spark that makes an audible noise can indicate a faulty light switch.

The bottom line is, light switches are typically not repairable. If you’re experiencing any of these issues, then it makes the most sense to remove the faulty switch and replace it with a new one. You may think this is something you can’t tackle on your own, but with the right tools and a few simple guidelines, you’ll be able to replace your switch in no time.

Prepare to repair

All you need to replace a switch are a few simple tools, many of which you probably already have around the house:

  • A reliable voltage tester
  • A flathead screw driver
  • A Philips screw driver
  • Some needle nose pliers with wire cutting capabilities
  • A wire stripper

These are all pretty common tools, save for the voltage tester. A voltage tester is used to determine the presence of electricity in a piece of equipment that you’re testing. It is also used to determine whether adequate voltage is present in a wire. Look for a tester rated for up to 500 volts.

Put on your troubleshooting hat

If your light fixture has new bulbs and you’ve made sure that no circuit breaker is tripped, and when you flip the switch to the “on” position the light won’t come on, (or it flickers on and off), you can assume there’s a problem. A tripped breaker does not go all the way to the off position. Instead it will remain positioned in the middle and still have “play.” It won’t reset unless you turn it completely to the off position. 

Once in the off position, you can turn it to the ON position. If your light comes on, the issue has been resolved; if not, continue troubleshooting.

  • Safety first: Before you do anything, make sure the circuit breaker to that particular light is turned to the “off” position (see above). You may also want to use a circuit tracer to identify the circuit breaker or fuse you need to turn off. A circuit tracer is a device for locating electrical circuits in walls and floors and for identifying circuit breakers. It can associate the correct circuit breaker with a particular electrical outlet.
  • If you are using a non-contact tester, touch each of the 2 screws with the tip of the tester. You’ll know there is no power if it doesn’t react. If it lights up and makes noise, you still have power.
  • To do this, set the device to AC voltage. With one probe, touch one of the screws and with the other probe touch the bare ground wire. If you get no reading, touch the other screw on the switch, wait a few seconds and remove the probes.  If you don’t have a reading, you know the power is off. Then remove the switch from the electric box by using the Philips head screwdriver to loosen the top and bottom screws on the switch, as well as the ground screw if present.
  • Remove wires from the switch: Take note of what color wire is connected to what screw-in switch. If the wires are connected to the back of switch, clip the wire right as it enters the switch and remove it. If this the case, you’ll have to remove about 5/8″ of insulation. Or, if the wires are looped around the screws, simply loosen the terminal screws using a Philips head screwdriver and remove both wires from the switch.
  • Connect the new switch: Using wires removed from old switch, connect new switch loosening two terminals on new switch and connecting the appropriate wires by looping them around the terminal screws in the same configuration you noted with your old switch.  Tighten each terminal screw to secure the wire to the switch.
  • Place back on the wall: Once connected, push the switch back into the electrical box and secure the top and bottom screws to electrical box. Position the cover plate over the switch and screw the top and bottom cover plate screws to the switch.   
  • Test it: flip the breaker back on and see if the problem’s been solved. If not, it might be time to bring in a pro.

Cost and length of time

The most common light switches in a home are called “single pole” switches. A new single pole switch costs between $0.75 and $4.00, depending on the quality and style. Calling a pro to do the same job could cost from $125.00 to $250.00.

As far as an estimated time to repair, a professional should take no more than 45 minutes, if it is a simple single pole switch replacement. For a homeowner it could take much longer, depending on skill level.

Easy, affordable remote diagnosis with Anew

If your light switch continues to not work correctly, it may indicate a more serious issue.

Anew offers an easy, efficient and affordable remote diagnosis service. For only $20 we will connect you (via video call) with a fully certified electrical expert with over fifteen years’ experience, who will walk you through the process of finding the issue and help determine the best way to solve the problem affordably. Contact an Anew representative for more details. 

Get a remote diagnosis

Video chat with an expert to pinpoint your home’s issues, then get them repaired fast.

Start My Repair

Get a remote diagnosis

Video chat with an expert to pinpoint your home’s issues, then get them repaired fast.

Start My Repair

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