I'm replacing the dimmer for my chandelier with a switch. It's a split-foyer home so I have a switch at the bottom of the stairs, the foyer, and the top of the stairs.

I know it's a four way switch circuit because of the three switches. I have wired one four way switch (top of stairs) and one three way switch (bottom of stairs, end of run I believe; only one wire coming out of the box) following various diagrams on this forum.

My question/problem revolves around the dimmer I'm replacing. The top switch has two red wires and the foyer switch has two red wires as well. This confuses me because all of the diagrams I've looked at seem to require a four way switch for two red wires but since there are only three switches, I'm assuming I only need two 3ways and one 4way.

If this the case, and I only do need one more 3way, how do I wire the 3way with the two red wires? Also, there is a single pole in the gang as well that controls the outside lights that is confusing me as well.

I'll attach images of all three gangs here. top, with the four way switch
enter image description here

foyer, switch in question with the single pole
enter image description here

bottom, end of run I believe
enter image description here

  • How was the missing dimmer switch wired originally?
    – JACK
    Commented Aug 5, 2020 at 15:39
  • Two black leads, one blue lead and one green lead. Green was tied to the grounds in the back of the box. I don't recall where the other ones were tied to. I do remember all the whites were tied together. Honestly not sure where the blue went.
    – Forddj1
    Commented Aug 5, 2020 at 16:24
  • I can't make hide nor hair of the wiring in the middle box. The directions the wires are going is hard to follow, and the wire-nut is blocking the view of how these wires enter their cables. most of what I need to see. Don't disconnect anything else, but can you spread things out a bit more and take another picture? Commented Aug 5, 2020 at 17:32
  • i.sstatic.net/yzTXj.jpg try this, don't know if it's any clearer
    – Forddj1
    Commented Aug 5, 2020 at 18:50
  • How sure are you that there isn't a fourth location in play here? Commented Aug 5, 2020 at 23:47

1 Answer 1


In a very similar situation, I turned off the power and disconnected all the switches and in a logical sequence using a volt-ohm meter (or toner and receiver) I determined which box had the hot lead, which were just travelers (usually the one with two reds) and which connected to the light. I drew an image of the results and the diagram makes it much easier to ‘picture’ your circuits. You realize that a single red is the beginning or ending traveler connected to the four-way in the middle. Be aware that when you see another black-white in the same box it is likely another circuit not related to your four-way. You can use a three-way at the ends but only a four-way in the middle where the two reds are located. Of course it can be much more complicated if you have two separate four-ways in the same box or if the light is not at the end of the circuit but in the middle or beginning (where the ‘hot’ lead is found). That may be when you need to employ a real-live electrician.

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