# Weird electrical problem with light switches **URL:** \ **Category:** Factual Questions\ **Created:** [July 4, 2015, 1:07am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178 "2015-07-04T01:07:53Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![rsa](https://avatars.discourse-cdn.com/v4/letter/r/839c29/32.png) [@rsa](https://boards.straightdope.com/u/rsa)\ **Post date:** [July 4, 2015, 1:07am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/1 "2015-07-04T01:07:53Z")
In my kitchen there are paired multiway switches at each end of the kitchen. The multiway switches control four ceiling CFL flood downlights. The switches had been working fine although the lights have always been very slow coming up to full bightness. A few days ago the switches started acting wierd. This is probably TMI, but this is the behaviour of the switches. S1 = switch 1, s2 = switch 2 and “up” and “down” is just the position of the switch. S1 up, S2 down lights off S1 down, S2 down lights on S1`down, S2 up lights still on but a flicker when changing S2 from down to up S1 up, S2 up lights still on S1 down, S2 up lights on S1 down, S2 down lights on (as above), but a flicker changing S2 from up to down Also, sometimes now for the first time the lights come on at full brightness immediately. I was planning to replace switch 2, but I thought I’d get some sage advise from the experts in residence first. Do I need an electrician? ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [July 4, 2015, 1:22am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/2 "2015-07-04T01:22:00Z")
I had to make myself a little diagram to see what this was all about; I’m a visual kinda guy. Yes. To me it sounds like one of the poles on S2 is flaky. Turn off the breaker and replace S2. And please report back! ---
**Author:** ![boytyperanma](https://avatars.discourse-cdn.com/v4/letter/b/4491bb/32.png) [@boytyperanma](https://boards.straightdope.com/u/boytyperanma)\ **Post date:** [July 4, 2015, 1:42am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/3 "2015-07-04T01:42:53Z")
Swap switch 2. Make sure you keep track of the wire that is connected to the black screw. If there is no black screw it gets easier to screw things up. The two other wires are carriers and can be connected to either brass screw to no I’ll effect. When you have the box open check all Wire nuts to ensure they are making solid conections. ---
**Author:** ![wolf\_meister](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolf_meister/32/15202_2.png) [@wolf\_meister](https://boards.straightdope.com/u/wolf_meister)\ **Post date:** [July 4, 2015, 1:44am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/4 "2015-07-04T01:44:14Z")
I’m assuming that the circuit works with what electricians call “3 way switches”. Make sure that you replace S2 with a 3 way switch _ **and** _ make sure you remember which wires went to which terminal on the switch. I’m very familiar with this type of circuit so fell free to ask me all the questions you want. ---
**Author:** ![rsa](https://avatars.discourse-cdn.com/v4/letter/r/839c29/32.png) [@rsa](https://boards.straightdope.com/u/rsa)\ **Post date:** [July 4, 2015, 1:56am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/5 "2015-07-04T01:56:39Z")
I’ll replace the switch tomorrow. I have an extra switch with a green wire which seems to be ground and two black wires. Does it sound like that would work or do I need to buy a 3-way switch? ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [July 4, 2015, 2:01am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/6 "2015-07-04T02:01:15Z")
You need to buy a three-way switch. Ground is a given on all switches and is not to be confused with a terminal connection. As others have stated, replace the swiitch keeping close notice of the black wire/terminal. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [July 4, 2015, 2:49am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/7 "2015-07-04T02:49:46Z")
Take a photo of the wire connections to the switch with your phone. cheap insurance just in case it gets confusing. a photo will make it clear how it was wired originally. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [July 4, 2015, 3:13am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/8 "2015-07-04T03:13:41Z")
Maybe I’m lazy. I wouldn’t try to figure out which switch is bad. Change both. 😉 Problem gets solved on the first try. Just be careful to buy the correct replacement switches, take a photo of the original wiring, and hook everything up correctly. Have a beer and enjoy the rest of the holiday. ---
**Author:** ![wolf\_meister](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolf_meister/32/15202_2.png) [@wolf\_meister](https://boards.straightdope.com/u/wolf_meister)\ **Post date:** [July 4, 2015, 3:17am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/9 "2015-07-04T03:17:56Z")
As Leaffan said it _ **must** _ be a 3 way switch. A 3 way switch will have 3 terminals as well as a grounding screw. It will look like [this](http://www.1728.org/3way.png) Notice that a 3 way switch will _never_ have “on” or “off” printed on the switch handle. And I like aceplace57’s suggestion - “buy two 3 way switches” ---
**Author:** ![TSBG](https://avatars.discourse-cdn.com/v4/letter/t/77aa72/32.png) [@TSBG](https://boards.straightdope.com/u/TSBG)\ **Post date:** [July 4, 2015, 3:20am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/10 "2015-07-04T03:20:29Z")
It might be that the wiring is affecting the brightness–I’m not competent to comment on that–but I have some CFLs that definitely start dimmer when the house is cold, but come to full brightness immediately when it’s warm. Could that be separate from the wiring issue? ---
**Author:** ![rsa](https://avatars.discourse-cdn.com/v4/letter/r/839c29/32.png) [@rsa](https://boards.straightdope.com/u/rsa)\ **Post date:** [July 6, 2015, 1:02am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/11 "2015-07-06T01:02:01Z")
The hardware store was closed yesterday but I bought a 3-way switch today and just now installed it (switch 2 location). The good news is that it appears that the lights consistently come on at full brightness. The bad news is that the odd switch behaviour still exists. I’m done for tonight, but I may try replacing switch 1 tomorrow although I’m not hopeful that that will make any difference. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [July 6, 2015, 2:32am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/12 "2015-07-06T02:32:24Z")
What odd switch behaviour still exists? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [July 6, 2015, 11:54am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/13 "2015-07-06T11:54:39Z")
From the OP, if S2 is UP, then the lights are on regardless of S1’s setting. What makes no sense to me about that part of the OP is he implies this behavior is new or different from historical. Which may simply mean that he never noticed it before, but when the flickering & dimness got bad enough he finally paid detailed attention to the switch details. If I’ve accurately described his description and that description is accurate to reality, then he has now, and had before, a wiring problem in addition to a flaky S2. Which could be a lost neutral, a botched switch replacement in the past, or any number of other fun possibilities. My advice at this point is to look carefully at S1. If it IS a 3-way AND all connections are firm AND it looks & feels mechanically healthy, then you’ve got a wiring problem. Call an electrician because the possibilities are too numerous and far-flung across the house to be safely solved by an amateur using remote diagnosis by messageboard. If S1 or its connections look flaky, replace it, being very sure to get all the wires back on the same terminals. If that still doesn’t fix it, call an electrician. And tell him/her what you’ve already done. ---
**Author:** ![rsa](https://avatars.discourse-cdn.com/v4/letter/r/839c29/32.png) [@rsa](https://boards.straightdope.com/u/rsa)\ **Post date:** [July 6, 2015, 11:37pm UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/14 "2015-07-06T23:37:57Z")
Thanks, and while I can’t swear the lengthy warm up time (or lack thereof) isn’t just a random thing, the switch behavior is definitely new as both switches were used all the time. I’ll post an update after I check S1. BTW, the “flickering” is not really that, it’s just an almost imperceptible (near instantaneous) single flicker . ---
**Author:** ![rsa](https://avatars.discourse-cdn.com/v4/letter/r/839c29/32.png) [@rsa](https://boards.straightdope.com/u/rsa)\ **Post date:** [July 12, 2015, 1:57am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/15 "2015-07-12T01:57:17Z")
Well, I finally got around to replacing switch 1 (S1) and that solved the problem. Just wanted to let those who helped know the outcome and provide my thanks for the input. ---
**Author:** ![wolf\_meister](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolf_meister/32/15202_2.png) [@wolf\_meister](https://boards.straightdope.com/u/wolf_meister)\ **Post date:** [July 12, 2015, 6:21am UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/16 "2015-07-12T06:21:29Z")
**rsa** I’m glad you solved the problem. 🙂 ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [July 12, 2015, 2:32pm UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/17 "2015-07-12T14:32:56Z")
Yaay! And yes, we (I at least) do appreciate getting the resolution on these fixit threads, even if it’s a couple months old. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [July 12, 2015, 4:09pm UTC](https://boards.straightdope.com/t/weird-electrical-problem-with-light-switches/724178/18 "2015-07-12T16:09:19Z")
I guess it’s too late to recommend this, but I’ve heard that electric current can cause a slight bit of vibration, so that over time this slight vibration can actually loosen the electrical connections. If you’re competent at switching off the breaker or unscrewing the fuse, then go through everything and tighten up all the screws and give all the wire nuts a bit of a twist. Sometimes that helps …