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double light switch issue

On the stairs to my basement is a light that is controlled by 2 different light switches, a basic single light switch at the top of the stairs and then one of the switches on a combo switch (the other switch controls the garage light). It has always worked well until this past month. Now, if you turn it on with the upstairs switch it turns on and off fine at either switch, but if it is turned on with the downstairs switch, it will stay on when you turn off the upstairs switch. I hope that makes sense.  I have no idea why it would all of a sudden do that and have no idea how to fix that. Any ideas? 

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Posted 2014-09-16T13:24:17+0000  by kjpayne kjpayne
If it's been working fine it's probably the switch and based on what you describe happening, I'd suspect the downstairs (double) switch.  Unless the garage is controlled from another location you'd need a double switch that is half "regular" and half three way such as this one from Leviton.  Make sure you turn off the power before opening the box.  It's also a good idea to take a couple of pictures of the wiring before you start.  If you're unsure of your ability to make electrical repairs, hire a licensed electrician.

Posted 2014-09-17T12:11:58+0000  by Adam444
Good morning kjpayne,

Thanks for your question and welcome to the community!

Without seeing exactly how your 3-way wiring is setup, there isn't one surefire to say what the culprit is as of now.

However, if it just went out as you say it did, you'll need to turn the power off first leading to the switches.

Use a non-contact voltage tester (shown below) to ensure no wires are energized once you start troubleshooting.

Before taking off any wires but after removing the wallplate to view the switches, carefully inspect all terminals and connections. It can be something as simple as a loose wire, or something a bit worse.

In either case, you'll need to inspect both switches, replace them (you'll be out less than $10 for both of them), and make sure they were wired as they were configured before. In cases where the switches suddenly fail after years of use, it sometimes can be a simple replacement.

Let us know if you have any further questions, and best of luck on your troubleshooting. Keep us updated, if possible.

Posted 2014-09-17T12:14:54+0000  by Joseph_HD_ATL
Adam, thanks for your response. I opened it up last night and the downstairs is actually separate switches covered by one cover so that's why the garage light is unaffected probably. Now, since the downstairs one with the issue is separate, is that a regular switch or is it s three way switch? How do I know what it is?
Posted 2014-09-17T12:16:22+0000  by kjpayne
Hey again kjpayne,

A single pole switch refers to one switch that control a light(s), a 3-way switch refers to a switch that has another switch controlling a light fixture(s).

In your case, a 3-way would control the garage lights from the bottom of the stairs, and at the top. To find out more about 3-way wiring, click here to view how to wire it.

Replacing a 3-Way Switch

The combination switch is supposed to be a single pole and 3 way combination switch, so you'd need to replace that exactly as it was to ensure it will operate again. The combo switch has a tab on the side of it that allows to 'break' or separate the switches. Inspect the wiring terminals and replace them as it was before.

If this still doesn't work for you, check with a licensed electrician in your area, who can do further in-depth troubleshooting.

Let us know if you have any further questions,
Posted 2014-09-17T12:40:24+0000  by Joseph_HD_ATL
If the light switches from two locations, then it's a three way switch.  There's a couple of ways to tell for sure.  Three way switches won't have "on" and "off" marked on them.  If you look at the back of the switch, a thee way will have an extra screw terminal for the "common" wire.  For a three-way circuit to work properly, both switches must be three-way.


You can test the switch.  Since we think it might be the bottom switch, turn off the power and pull the upper switch out of the box.  Connect either of the travelers to the common wire using a wire nut.  Push the switch out of the way so it can't touch anything or remove the remaining traveler and cap it with a wire nut.  Turn the power back on and test the lower switch.  The light may come on immediately after turning on the power, operating the switch should turn it off.  If the light is off, the operating the switch should turn it on.
Posted 2014-09-17T14:53:01+0000  by Adam444
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