Can a light switch go bad? How to tell

Can a light switch go bad? The answer surprises some people, but yes, being an electromechanical device, there are parts in a light switch that can wear out or become oxidized over time and eventually stop making good electrical contact. In this blog post, I’ll explain how to tell if your light switch is going bad and if it’s time to replace it.

Your light switch clicks

One symptom I’ve frequently heard is that a light switch that clicks means it is going bad. Depending on what causes the click, that may not always be the case. In the past, some lights switches gave a mechanical click as you turned them on. I even found a stash of new old stock, unused light switches from a long defunct hardware store chain in the garage of a house I was renovating. Those switches clicked audibly when I operated them.

To know for certain if a click in the switch is problematic or just the way it was made, you can unscrew the bulbs from the light fixture so the switch isn’t controlling anything. With no load on the switch, there won’t be any electrical current. If you flip the switch and it still makes a noise with the bulbs unscrewed, that’s a mechanical sound. If the click goes away without a load, that’s the sound of electricity fighting resistance, and you don’t want your light switch to be putting up a fight.

All that said, sometimes people replace old light switches just because they want a quieter switch. If a click from your light switch bothers you, a new, quiet light switch is a quality of life upgrade that doesn’t cost a lot of money. New light switches cost about $1.

Sparks and other noises from the switch

Similarly, if you hear other noises when you flip a light switch, those noises are usually an indicator of electrical resistance. And if the problem seems to become more frequent over time, you’re not imagining things. That sound you hear is called arcing, and arcs attract dust and deposit the dust on the metal surface nearby. Every time this happens, it makes the arcs happen more frequently.

Sparks from a light switch

Generation X may remember parents telling us not to operate a light switch with wet hands, because it causes a spark and it could shock you. There’s less danger of that today since grounded light switches are much more common now.

If you operate a switch with dry hands and it sparks, that’s a good indicator of the switch is going bad and needs to be replaced.

Light bulbs burning out prematurely

Energy efficient light bulbs do more than save money. They also last longer. I got into the habit about 20 years ago of writing the date of purchase on my bulbs because I bought a bad batch that only lasted a few months, and back then bulbs were really expensive, so it meant I wasted a lot of money.

I learned two things from doing this. Sylvania bulbs gave me more problems than any other brand, and my bulbs didn’t last as long in bathrooms, regardless of brand.

I replaced the switches in my bathrooms and solved my problem. Most of the bulbs in my bathrooms are between 5 and 7 years old now.

Can you fix a light switch that went bad?

In theory, you can fix a light switch, but it usually is more trouble than it’s worth. New light switches cost around $1 and you will spend nearly a dollar in cleaning supplies and effort refurbishing a light switch that went bad.

But if you are a preservationist and you want period correct switches in an older house, cleaning an old switch in an ultrasonic cleaner will revive them if the problem is dirt or oxidation. If the problem is worn contacts, an ultrasonic cleaner won’t help.

So fixing a light switch is risky, but sometimes possible. You’ll have to decide if it’s worth the trouble for you.

If the light switch is dirty on the outside, it must be bad, right?

I’m sure you’ve heard people say their rule is if it’s dirty on the outside, it’s dirty on the inside. When it comes to light switches, dirt on the outside could be an indicator that there is dirt inside as well. But the opposite isn’t necessarily true. You can clean the outside of a switch, but cleaning the outside of a switch doesn’t do anything to help inside a switch.

And the things that cause a switch to get dirty on the outside aren’t the same as on the inside. The outside of switches gets dirty from use. The inside of switches get dirty from arcing and humidity as much as anything else. A light switch in a garage in Arizona doesn’t get much humidity, so it will last longer than a switch in a garage in Missouri, where it will be exposed to humidity accompanied by greater swings in temperature.

So the rule that a switch is similarly clean on the outside and on the inside is based on the assumption that cleanliness and humidity are related. That’s not a reliable assumption.