I’m trying to change out an old dimmer switch with a new single pole or 3 way dimmer switch that has a black, red, optional red for the 3 way, and a ground terminal. My old dimmer has two black wires coming out of it and nothing else. There’s a bunch of neutral wires and ground wires in the junction box but none connecting to the dimmer. How do I wire this up? Pictures below. Thanks very much.

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  • the left one is your old 3 way switch
    – asinine
    Oct 15, 2022 at 19:50
  • A picture of the dimmer you are trying to install would help. Generally A white lead will be tied to the white neutrals, Green to ground black to the hot lead and red to the load or the light.
    – RMDman
    Oct 16, 2022 at 2:17

1 Answer 1


In the box the dimmer came in are detailed instructions.

Cap off the red and white stripe wire, hook the red from dimmer to one of the blacks from the wall box and hook the black from the dimmer to the other black from the wall box. You will want to (need to) add a pigtail from the ground bundle in your box to hook up to the ground terminal on the switch. This can be simple if they are wire nutted together- often they are crimped together which is more difficult.

  • Hi I’m so sorry I wasn’t more specific, but I am trying to change out the dimmer on the right, not the switch with the red wire. Thank you
    – Ryson
    Oct 15, 2022 at 23:47
  • Yes, as stated black from new switch to one of the blacks from the wall box and the red from the new switch to the other black from the wall box. Wire each separately with a wire nut. And then of course hooking up the ground and capping off the red/white from the switch (which is used only for 3 way configuration).
    – Kyle
    Oct 16, 2022 at 1:50
  • Thanks for all the help everyone!
    – Ryson
    Oct 24, 2022 at 17:18
  • @Ryson if you'll take the tour, you'll note that the appropriate way to say "thanks" is to click the up vote button next to every answer that was helpful to you, then to click the check mark next to the answer that helped you the most.
    – FreeMan
    Nov 15, 2022 at 16:43

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