Troubleshooting 3-Way Switches: Why Does My 3-Way Switch Only Work Sometimes?

Thank you, this made a lot of sense and you explained very well. I couldn’t figure out why the 3 way I replaced was acting oddly — I matched the wiring when I took it out.

Turns out that the new Leviton Switch I installed had the common wire screw swapped from the original I took out! Learned a lesson — I can’t just match what I pull out!

I have the same MIlwaulkee drill. Love it for the light work.

Thank you very much ... I was lost for an hour... I think I flipped wires for about 40 mins... Got it now thanks alot

Thanks Man! I had this exact problem and thanks to this video I learned how to fix it. The important part that allowed me to see what went wrong was where you identified that the 2 travelers needed to be in the same sheath. Great instruction!

You're stud markings are backwards 😂 you're showing to nail at the bottom of the box

Dustin, Thanks for a great channel. I have a question about multiple 3 way switches in the same J-Box. So, when you enter my Tiny House and on the left is a wall switch, with 4 different 3 way switches. Each 3-way switch controls a different operation. One does ceiling lights, the other does Front porch lights, the third 3-way controls the deck lights and the Fourth 3 way switch controls an outlet at ceiling level for a rope light (LED). I know I can run 14/2 from the panel to the J-box and get power to the switches. Here is where I'm a bit unsure! I need to run 14/3 to the other J-Box that has Four 3 way switches that operates the same as the front door J-box. Do I have to run 4 different 14/3 runs? is there a way to combine those runs onto just one run? and if so how might that work? Thanks for your help!

As an electrician of 4.5yrs I was actually flabbergasted that I was stumped by a three way switch. Ended up being a burned terminal. Ended up needing someone else's eyes on it.

🙏 thank you

ok I have two lights and two double switches I went two change one of the double switches no can do. cant get it wired right. I have two red wires and three black wires coming into the box. any idea how the wires are to connect to the switch?

Thanks so much for this. Was pulling out my hair trying to figure it out

This was exactly my issue! Thanks for your help

I did what you suggested (swap swapped what I thought was the traveler ) and still have the same negative result.
Could there be another reason?

Thanks, I have this problem in my hallway, it annoys my wife.

Swapping out old 3-ways in a 1964 house I just bought. Was so confused why they weren't working properly after the swap

Watched this video & when you said to look at the sheathing to see which one had 1 wire coming out & which one had 2. Thats all I did & now it's fixed good as new!

You're the man thanks so much

I always set up my three ways that they’re both off when the lights off this stops a lot of service calls same thing with four ways. If you’re doing your checks and one of them stupid switches and then the on position and the light is off switch to travelers at one location. This will help prevent service calls lol.

INEED HELP I HAVE GREEN,BLUE,AND YELLOW WIRE ON A THREE WAY

Thank you thank you problem solved

My dad taught us basic electrical growing up. I always knew it was called a 3-way switch, I knew that's what they did but I never knew WHY it was called a 3-way switch. I always thought it should be called a 4-way switch. You Sir, made it make sense. The guy working on our house recently wired the hallway light leading upstairs and you have to keep the one at the top of the steps flipped to the up/on position in order to use the one at the bottom of the steps that is in the kitchen, to turn the light on. We had always had these switches in that stairwell but after our house fire (of course an electrical fire but not because of this particular switch LOL) the electrician at the time never even put a hall light back in at the top of the steps. So.....with that being said, I now know how to investigate the issue. If he has the wires correct, as you showed, then I'll have to come back and watch a follow up video from you. hahahaha
We'll try this trick first because the way you explained it, I followed intently and realized that the problem is in fact the one at the bottom of the stairs in the kitchen and is not the one at the top of the steps that is having the issue. You even made that easy to understand. Easy peezy. BTW....you forgot to act surprised when the light came on at the end. LOL

~ I can see why your content qualifies for continuing Education .... I learn alot from it ~ that I didn’t quite get from my AA Building inspector degree instruction

Funny ass slang words electricians use for their three-way wires....traveler, common, pigtail, leg....like something from the cartoons.

I'm still having an issue and hoping you could help, I've been stuck on this for days now and banging my head against a wall...I simply replaced the two switches with new ones and the old one had 14-2 black to common, and 14-3 black and red to travelers, I did the same for both switches and now one switch will flip on and off, and when turning that off, the other switch won't turn on...here's the twist, if I flip the other switch one, the initial switch won't turn on, so it's happening to both switches where one can have the power and the other won't....PLEASE HELP!!!

This just happened to me but our house was built 2 years ago and we never had a problem. 3 hallway lights, all 3 can turn on or off with 3 switch locations. Bottom of stairs, top of stairs, end of hallway. And it's not the lights.

The point about the shared sheathing was very useful. Hard to tell which wire is what with a 1930's home. Thanks!

😂❤ Thank you for this!! I think I’ve got too many hot wires—the lights won’t shut off! (That’s what you get when you work through the night. So not worth it!😂❤)

Thank you !

I just replaced some very old 3-ways in bakelite with all brass screws. The bakelite was stamped COM. The new Decora switches had the black screw, and each end of the run had two wires coming out their own separate sheathing. Bazinga! COM wire to the black screw, and the other two don't matter, tie 'em to the brass.

Thanks for the common comment, the pos 3 way switch I was provided has no blacks screws and no instructions in the box, just two brass screws and a chrome screw. I got it fixed now.

I realize that you wired this instructional setup, but why did you use a #14 and a #12 at the same switch?

What happens if the traveler is hot but not the switch leg? I tested the wires with breaker on, and the switch leg has nothing but the traveler is hot. Replaced the three way about 2 weeks ago and it’s suddenly not working

50 years ... We moved into our family home in '74, and the 3-way in the garage did not work correctly. it only affected the lights over two of the spots. Dad refused to fix it, and later he refused to let me look at it. Well ... he passed a couple of months ago, and I've been working for weeks fixing everything he refused to fix. And guess what ... the old garage 3-way works now! The travelers at both ends were mis-wired just as in the video.

Thanks for this

Great video. Got my switches fixed in minutes. Thank you!

You don't even know bro. You changed my life! THANK YOU!!

Great and simple explanation Thank you

What the hell is a Chicago 3 way?

Helped me rewire a bunch of old switches!

I was going CRAZY! And didn’t understand anything you said until you explained both travelers are coming out of the same spot…. NOW MY 3way works! Thank you so much

Have 2 circuits like these where depending on where one switch is toggled the circuit is off regardless of the position of the other switch.

3 way switches: one switch takes power and the other takes the Switch leg of the light.

Fixed my issue thanks

BEGINNERS: its crucial you remeber that there are two separate legs. Switch side and hot side. Do not spend hours on farting around with one switch because you dont want to keep walking back and forth. Identify the circuit first before troubleshooting!

Thank you

I had the same issue, but this was not the cause. I had a loose terminal in an older house and as such only one leg was ever active.

This video solved the exact problem I was experiencing. Thank you!

You helped so much with this video. House was built in the 60's and i was struggling to get the 3 ways working again after a remodel

My light will only turn on with the switch that last turned it off. So at any point in time one or the other won't work, just depends on which one flipped the light off last.

If you swap the travelers on the one switch that's up when the light is off you can have both switches on the off position when the light is off

This is a great video. I am replacing a non-working switch on a three way with a Lutron 3 way dimmer switch for a very high front hall chandelier. This is the second attempt with the 2nd switch I purchased, and once installed, the light fixture glints on for a milisecond, then turns of immediately and never goes back on. Would love your opinion. Thanks!

Also, The replacement 3 way switch looks different than the original. There is a green grounding wire coming from the back. Whereas the original has a loop that you put under the screw.

Good video.
I bought a house (built 1956) and replaced both 3 way switches. one of the switches has a dimmer and installed a recessed light. The switches work but when both switches are off, I can still see a very dim light coming from the LED light. What am I doing wrong? Any help will be appreciated. Thanks!