We've all been there - flipping a light switch on and off repeatedly, jiggling the switch plate, and tapping the switch in vain attempts to get a stubborn light to turn on. Dealing with a faulty light switch that intermittently works can be endlessly frustrating. But before you call an electrician or replace the switch, there are a few easy troubleshooting steps you can try yourself to get that pesky switch working properly again.

What Causes Light Switches to Malfunction?

Light switches can malfunction for a variety of reasons:

Loose Wire Connections

The most common cause of a flaky light switch is loose wire connections. Light switches are wired to the light fixture using electrical wires secured with screw terminals on the side or back of the switch. Over time these connections can become loose due to vibrations, thermal expansion and contraction, or simply old age. Loose connections cause poor contact between the wires, making the circuit unpredictable.

Faulty Switch

While less common than loose wires, a faulty switch can also be the culprit behind a switch that only works sometimes. The metal contacts inside a switch can become burned or corroded over time, preventing them from properly completing the circuit when the switch is turned on.

Overloaded Circuit

An overloaded circuit can also cause intermittent problems with light switches. Having too many devices like lights, outlets, and appliances on one circuit places excess strain on the switches controlling them. The extra current draw can cause heat and connection issues.

Old House Wiring

In an older home with outdated wiring, light switches may not work reliably due to inadequate or deteriorated wiring that isn't up to current electrical code standards. Aluminum wiring in particular was used in houses built between 1965 and 1973 and is prone to overheating.

Simple Light Switch Troubleshooting Steps

Before replacing a faulty light switch, there are a few basic steps you can take to troubleshoot and fix the problem:

1. Check for Tripped Circuit Breakers

The circuit breaker connected to the troublesome light switch may have partially tripped, causing power to the switch to become interrupted. Check your circuit breaker panel for any tripped breakers controlling the light switch circuit, and fully reset any you find.

2. Inspect the Light Switch

3. Eliminate Bulb or Fixture Issues

To isolate the problem to just the switch, remove any bulbs from the light fixture controlled by the problematic switch. Then turn the switch on to see if the contacts properly connect and stay closed. Similarly, try temporarily connecting a basic lamp to the switch instead of the installed light fixture. If the basic lamp turns on reliably, the problem may lie with the light fixture instead of the switch.

4. Clean the Light Switch

Turn off power at the breaker panel. Then unscrew and remove the switch from the junction box to clean the switch contacts. Use rubbing alcohol and a toothbrush to gently scrub and remove any dirt, oxidation or debris on the contacts. Allow contacts to fully dry before reinstalling the switch.

5. Replace the Switch

If cleaning the switch contacts and tightening connections doesn't fix the problem, the switch likely needs to be replaced. Turn off power to the circuit, then remove the switch and disconnect the wires. Install a new switch with the same amperage rating and connect the wires to the corresponding terminals. Securely tighten all wire terminal screws on the new switch before restoring power.

When to Call an Electrician

While a malfunctioning light switch is usually an easy DIY fix, there are times you may want to call a licensed electrician:

Paying an electrician for a quick light switch replacement or repair is much cheaper than dealing with the potential hazards of DIY electrical issues beyond your skill level.

With some basic troubleshooting and a few simple repairs, you can get that pesky light switch working properly again. Just exercise caution when working with electrical wiring and devices. With the right knowledge, a little effort can save you the hassle and expense of replacing a switch unnecessarily. So next time you go to flip a switch and the lights refuse to cooperate, try these handy tips before calling for an electrician.