Fixing some switches and adding Wifi switches to a home I just bought. I pulled out some old style switches from this box and added 2 WiFi switches plus a 3 way paddle on the right. I believe a 3-way switch was on the right before since it controls a light controlled by one other switch down the hall(might’ve been the middle switch though.. idk). Anyhow, I’ve managed to get the two WiFi switches working like I want them to but I’ve got a smattering of leftover wires and can’t get my 3-way to power it’s light no matter what I try. What am I missing in this rats nest? enter image description hereenter image description here

  • See the /3 cable in there, top left? Where does its white wire go? – Harper - Reinstate Monica Jul 13 '19 at 18:34
  • Hello, and welcome to Home Improvement. There's no way we could figure out where the wires come from/go to remotely; you should add a diagram showing it all. And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Jul 13 '19 at 18:38
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    Taking good notes before disconnecting is a lesson you have just learnt... disconnecting the supply and using a multimeter to trace what is going on is the way forward. – Solar Mike Jul 13 '19 at 18:46
  • Do either of the red and black wires from the far leftmost cable have power? Does which of those wires has power change when you flip the switch down the hall from here? – ThreePhaseEel Jul 13 '19 at 19:17

This is a long slog, but it's straightforward. You have at least 7 cables. The 3-way circuit and 3 switches can explain 5 of them at most.

Don't unhook anything else.

First, since you know there's one of a pair of 3-way switches here, Romex Cable #1, the /3 cable, can be positively identified as being for the 3-way circuit, since nothing else would work. Fortunately we see its white wire join four other black wires, so white is being used to send always-hot to the other 3-way. The other two wires (red and black) are travelers. Mark them both with yellow tape so they can be easily recognized as travelers. The common terminal on this 3-way switch must therefore go to the lamp. That would be a cable where the white joins other whites, but the black is in search of this 3-way switch. It looks like you have that exact situation on Romex #4.

Romex cable #7 and #6 both have their hots going to a wire-nut (the one with the 3-way white). That means one of them is supply, and the other one takes power onward to another point-of-use. It doesn't really matter which one is which.

Romex cable #5 black seems to go to the smart switch on the left, so presumably it goes to the lamp controlled by the left smart switch.

Romex Cables #2 and #3 have their neutrals going into the big bundle. Then, I can't quite tell, but it appears they have their hots joined together with a pigtail, which is then nutted onto the left smart switch. If this smart switch controls 2 lights, then this explains all the cables.

If the two installed switches are working, then all you have left to do is wire the /3 switch, yellows to brass, and solo black wire from #4 to black.

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