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I have an issue where the far left 12/2 coming from the circuit has been used to power a dimmer switch to a light Carry power from light to another light The second light is controlled by another switch at the end of the run. Issue - if 1st switch is off, the 2nd light will work from its switch. If 1st switch is on, the 2nd light wont work at all from its switch Based on the diagram is there anyway to fix this issue without current wiring setup? enter image description hereenter image description hereenter image description hereenter image description here this is the dimmer switch (A) for the first light (B) l old dimmer test switch

  • looks like it was a 3-way, not wired as a 3way at the moment. Was the 14/2 between the lights added by you or is it newer? The ? wire appears to be 12/3, so where is the other end? You need a new 12/3 between the lights (to complete a 3 way again), OR make the red hot all of the time and carry that through.to the second light via the 14/2 b&w
    – noybman
    Feb 2, 2020 at 18:39
  • 1
    BTW... carry the white through as white all of the time
    – noybman
    Feb 2, 2020 at 18:42
  • I think at one time, the red cap-off wire was a second hot wire for the ?cable in the second light box, which went to a third light. This was controlled by a double switch at the far switch point. The ? wires are is now too runted to use, so it is scrap. Feb 3, 2020 at 0:31
  • 1
    Just to verify, the breaker that controls this circuit is 15A, right? Feb 4, 2020 at 0:13

2 Answers 2


To have two switches/dimmer controlling two lights independently with the wiring we know you have:


The notation should be clear using your method, but if not, ask away.

  • Well I only want the dinner to control the first light and the end switch to control the second light. Does that make sense?
    – Tonkadog
    Feb 2, 2020 at 20:21
  • Yes, and that is what this does
    – noybman
    Feb 2, 2020 at 20:33
  • Perfect one question though, the dimmer switch I have has a black (power), red (???), white (neutral), and green (green) wire. Do I do anything with the red wire?
    – Tonkadog
    Feb 2, 2020 at 21:04
  • i.stack.imgur.com/g91UQ.png For switch 1 - dimmer switch - does white carry through and just connect to lights? - connect black to black and red of dimmer? For black wire - does black just carry thru and connect switches? For red - does it just connect switches to lights?
    – Tonkadog
    Feb 2, 2020 at 22:01
  • We don't see what switch/dimmer you have for "A";but yes, carry through the white,and the black via pigtails, but the red is the output to the light.
    – noybman
    Feb 2, 2020 at 23:12

Wow, what a fiasco. Was the original installer colorblind?

Note I am advising the same thing as Noybman, so I'm leaning toward the reasons for it rather than the procedure per se.

Let's color-code this thing, for Pete's sake!

I am a huge fan of color-coding wires to their purpose/function. In this case, 90% is already done for us. Let's review the color codes.

  • Safety Ground == Bare, green, yellow/green.
  • Neutral == White
  • Always-hot (hot at all times) == Black
  • Switched-hot from a switch to lamp(s) == Red

The savant who wired this stuff initially put all the correct types and colors of wire in the wall to match that scheme already. So that was easy.

Lights typically ship with black hot wires, and we don't want the light on 24x7, so use red electrical tape to re-mark them red.

The "Smart switches" on the market generally use black for always-hot and red for switched-hot, so that is already perfect. If they don't, consult their instructions and re-mark as needed.

Plain switches now attach to black and red. Doing this will bring the far-most switch compliant to the 2011 Electrical Code, which requires neutral be cabled to a switch even if a smart switch is not being used (yet).

So, in every box, you simply connect all blacks to all blacks, all whites to all whites, and all reds to all reds. And you're done. Simple like it oughta be.

  • The last switch in the series pictured isnt using red at all. To bring the actual neutral to the box as a neutral he can't connect it to the switch as pictured
    – noybman
    Feb 2, 2020 at 23:15
  • @noybman yeah obviously. I am advising OP to change that. Oh, I see what you mean. That language isn't clear. Fixed. Feb 2, 2020 at 23:24
  • definitely clearer now! The last paragraph about reds to reds doesn't work as written but there arent any reds for him to connect to other reds (ignoring the "?" wire)
    – noybman
    Feb 3, 2020 at 0:01
  • I'm saying to re-mark the lamp's black wires red. Feb 3, 2020 at 0:52

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