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Discussion Starter · #1 ·
I just found your forum and have a question about an existing 3 way light switch with a dimmer control on one of the switches.
It worked a few months ago, but now the light just turns on and off from each switch. The dimmer no longer dims the light,
I pulled the dimmer switch out of the wall and it appears that one of the red wires from the switch is not connected to anything.
I tried to take some pictures and will post them here. One of the black wires inside the box has a wire nut on it, but nothing is
attached to it.
Any ideas, Thanks.
Will
 

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I just found your forum and have a question about an existing 3 way light switch with a dimmer control on one of the switches.
It worked a few months ago, but now the light just turns on and off from each switch. The dimmer no longer dims the light,
I pulled the dimmer switch out of the wall and it appears that one of the red wires from the switch is not connected to anything.
I tried to take some pictures and will post them here. One of the black wires inside the box has a wire nut on it, but nothing is
attached to it.
Any ideas, Thanks.
Will

If it’s a 3 way all 3 wires need to be connected,can you figure out where the elusive black wire goes?
 

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Discussion Starter · #3 ·
I should be able to trace it, if I can find the breaker for this circuit. I checked all of the ones labeled lights and none of them control this circuit.
 

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3 way switches are confusing to a lot of people, but let me try to simplify it.
You take power to the dark screw or black wire of a dimmer. 2 separate wires go between dimmer reds and brass switch screws independently. The hot to the light goes to the dark switch screw or black dimmer wire (at the dimmer or switch not where the hot is at).
There are exceptions and different wiring arrangements, but this is the basics.
Your dimmer is probably burned out dimming wise.
 

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Hi, it looks like that Red conductor may have become disconnected, did it have a wire nut on it? I probably came off of the black.
 

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Discussion Starter · #6 ·
I was able to find which breaker controlled the dimmer and the 3 way circuit. It is wired very weird. This circuit is in the dining room but is also connected to the den almost 20' away. I tried hooking the loose red wire from the dimmer to the black wire. The lights still work, but the dimmer does not change the light level. Then I tired taking the dimmer out of the circuit, and putting wire nuts on the 2 black and one red wire that went to the dimmer. The other switch in the 3 way circuit will not turn the light on now. I then connected the two black wires together and capped the red wire. The other switch now turns the dining room light on and off, but it works in reverse. When the switch is down, the light is on. Another strange thing, I have a fluke proximity voltage tester and when the light is on, I do not pick up any voltage on the black wires, but with the light off I do.
 

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I was able to find which breaker controlled the dimmer and the 3 way circuit. It is wired very weird. This circuit is in the dining room but is also connected to the den almost 20' away. I tried hooking the loose red wire from the dimmer to the black wire. The lights still work, but the dimmer does not change the light level. Then I tired taking the dimmer out of the circuit, and putting wire nuts on the 2 black and one red wire that went to the dimmer. The other switch in the 3 way circuit will not turn the light on now. I then connected the two black wires together and capped the red wire. The other switch now turns the dining room light on and off, but it works in reverse. When the switch is down, the light is on. Another strange thing, I have a fluke proximity voltage tester and when the light is on, I do not pick up any voltage on the black wires, but with the light off I do.

Can you tell which end is your switch leg for the light? There are several different ways electricians normally do 3 ways. First off your 3 way has either 1 black screw and 2 gold screws or in the case of your dimmer 1 black wire and 2 red. Think of your 3 way switch or dimmer as a fork in the road. Everything either enters or leaves the switch on that black wire. Power could be coming in on the black and sending it back out on red wire 1 or red wire 2. It’s directing traffic. At the other switch in this description you’ll have a black screw and 2 gold screws. The fork in the road is reversed. Power is coming in on one gold screw but not the other at all times. Which one depends on which way the first switch is positioned. Sometimes it’s coming in on one then flip the first switch and then it’s coming in on the other. Now your second switch in this scenario is directing traffic out to your light on the black screw. Either there’s a connection to power and it’s on or there’s no connection to power and it’s off. There is no true on or off on 3 or 4 way switching. Going back to your first switch .if you reverse the position you reverse which red wire is sending out the power than your light comes on because it now has a path at your second switch.

Do you remember how your switch was wired originally? If the 3 way function was working on both as normal only it wouldn’t dim it’s probably the switch needs replacing and there was nothing wrong with the wiring. A dimmer function is only a limiting device other than that it’s still a 3 way switch. Can you get a better picture of all the wires in that box so we can see which wires are travelling together? There looks like a bunch of neutrals together at that box , it could be that the feed is at that box, the neutral coming in is tied to the white on the 3 wire going to the other switch , the black wire on your switch is tied to the black hots and the 2 reds are tied to the red and black that also go to your other switch. It could be several different ways. Somehow you’ll need to figure out where the wires all go as there’s no universal way only 1 right way to do a 3 way.
 

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I am sure you need a new dimmer. That is an old school $5 dimmer probably years old. When the red wire came loose, it could have shorted the dimmer out. I would use a 3 way swItch where the dimmer is to get the wiring straightened out and functioning before putting a new dimmer back in.
 

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Discussion Starter · #9 ·
Okay, I opened up the box that contained the dimmer and the other switch in the room that controls the dining room light. I hope you can tell from the pictures what is going on. I currently have the red wire that went to the dimmer capped off and connected the 2 black wires so that the switch on the other wall turns the light on and off. Circuit diagram 001.jpg Circuit diagram 002.jpg Dimmer box 001.jpg Dimmer box 002.jpg Dimmer box 003.jpg Switch 001.jpg Switch 002.jpg Switch 003.jpg
 

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Okay, I opened up the box that contained the dimmer and the other switch in the room that controls the dining room light. I hope you can tell from the pictures what is going on. I currently have the red wire that went to the dimmer capped off and connected the 2 black wires so that the switch on the other wall turns the light on and off. View attachment 654997 View attachment 654998 View attachment 654999 View attachment 655000 View attachment 655001 View attachment 655002 View attachment 655003 View attachment 655004


From what I can see it looks like on the 3 wire the white is twisted together with the black hots and at the other switch the white from the 3 wire is on the silver (black?) screw. Then the red and black wires from the same 3 wire are on the 2 brass screws? If that is indeed the case then at the box where the dimmer goes the black and red wires from your 3 wire will go with your 2 red wires of the dimmer as they’re travellers. By the looks of your drawing you have a 2 wire also, the white twisted with 2 other whites (neutrals) and a black (formerly elusive). That black from the 2 wire unless the volt meter shows it’s live , has to be your switch leg to the light and if it is indeed dead (0v to ground) than it goes to your black wire (common) on your dimmer. I can’t perfectly see what’s going on but if you have a black or couple blacks tied to the white on the 3 wire those should test 120v weather the other switch is on or off. If at the other switch all that’s on it is the red black and white only from the 3 wire than that switch is what some call the end of the line. Coming back to the dimmer box the black and white 2 wire if the white is tied to a white or two and the black that goes with is not fastened to anything right now should test 0v than that has to be the switch leg (out to your light.
 

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From what I can see it looks like on the 3 wire the white is twisted together with the black hots and at the other switch the white from the 3 wire is on the silver (black?) screw. Then the red and black wires from the same 3 wire are on the 2 brass screws? If that is indeed the case then at the box where the dimmer goes the black and red wires from your 3 wire will go with your 2 red wires of the dimmer as they’re travellers. By the looks of your drawing you have a 2 wire also, the white twisted with 2 other whites (neutrals) and a black (formerly elusive). That black from the 2 wire unless the volt meter shows it’s live , has to be your switch leg to the light and if it is indeed dead (0v to ground) than it goes to your black wire (common) on your dimmer. I can’t perfectly see what’s going on but if you have a black or couple blacks tied to the white on the 3 wire those should test 120v weather the other switch is on or off. If at the other switch all that’s on it is the red black and white only from the 3 wire than that switch is what some call the end of the line. Coming back to the dimmer box the black and white 2 wire if the white is tied to a white or two and the black that goes with is not fastened to anything right now should test 0v than that has to be the switch leg (out to your light.

Looking at the drawing again it appears that a neutral is sent to the switch and is attached to the switch,if that’s how it’s done it won’t work.
 

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Discussion Starter · #13 ·
A few weeks ago or so, with the dimmer wired into the circuit, the switch would turn the light on and off. And then from the dimmer side, I could dim the lights. I am not sure it ever worked as a 3 way circuit normally would, but the dimmer could be pushed to turn the lights on and off.
 
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