I'm trying to replace a light switch with a new z wave smart switch. Specifically, the old light switch has 2 black wires and a ground wire attached to it and it is the only switch that controls 1 LED light. The new z wave switch is an Eaton RF9601 and it has 4 output wires: white, black, red and blue. This is the wiring diagram provided with the switch: enter image description here And I am a bit confused with how (or if) my scenario is compatible with this z wave switch. I capped the blue switch output and connected the green output to the existing ground wire I had, and connected the black output to one of the existing black wires. The other black wire is what I wasn't sure how to connect. I tried connecting it to the red output and the light comes on but was very dim, when connected to the white output the light was completely off. Any suggestions for the correct way to wire this?

enter image description here

A = Black Wire

B = Ground

C = Black Wire

D = Neutral?

When connected with A -> Red, B -> Green, C -> Black, D-> White and the light does not come on at all when power is turned back on.

Based on suggestions in comments I tried connecting A -> Black, B -> Green, C -> Red, D-> White and the light flashes and immediately turns off when the power to the switch is turned on.

Adding another picture of box to help clarify:

enter image description here

Turquoise circles are ends of white wire (D) and red circles are ends of black wires coming into box.

  • 1
    Can you please post photos of the inside of the box you're trying to install this switch to? Commented Apr 26, 2021 at 1:40

3 Answers 3


The new smart switch requires a neutral so unless you have a couple white wires wire-nutted together in the box with the switch, you're out of luck using that switch. You'll need to get a switch that doesn't require a neutral.

If you have only two true black wires in the switch box, chances are you have conduit and you could pull some THHN from the ceiling to the switch and bring in a neutral but we'd need more pictures to verify that.


The white is your neutral, most likely

Given that you have a bundle of at least 2 white wires in your switch box, that is most likely the neutral connection that your switch needs to work. Connect the white wire on the switch to that bundle with an appropriately sized wirenut, and continue wiring the rest of the switch.

  • So when I connected the white wire on the switch to the white wire labeled as D in the photo and turned the power back on the light was completely off. So maybe that wire was not the neutral wire?
    – ez4nick
    Commented Apr 27, 2021 at 1:27
  • 1
    @ez4nick Be sure to connect the black wire from the switch to the always hot black wire in the box.
    – JACK
    Commented Apr 27, 2021 at 1:29
  • @JACK The capped black wires in the back of the box?
    – ez4nick
    Commented Apr 27, 2021 at 1:53
  • @ez4nick One of the two black wires from your old switch is always hot. That's the one that goes to your black wire from your new switch. If one of those goes to a group of black wires, then it the always hot.
    – JACK
    Commented Apr 27, 2021 at 2:00
  • @JACK Got it, before I think I had been connecting the black wire labeled as C in my photo to the black switch output. So then C goes to the red switch output and A goes to the black switch output?
    – ez4nick
    Commented Apr 27, 2021 at 2:26

If you have two black wires in switch box it should be two white wires, connected together. One black wire is phase coming from panel, it always hot. Connect it with black wire of new switch. Another black wire is going to load. Connect it with red wire. How you need short piece of wire to make a pigtail. One side connect together with white wires, another side with white wire of new switch. Terminate blue wire with wire nut or electrical tape. And connect ground.

  • OP should have white wires (i.e. neutral) in the box unless, of course, the power goes to the light first, then there's a switch loop running to the switch itself. This was a very common way of wiring switches that has only recently been banned because of the need of modern smart switches to have a neutral at the box.
    – FreeMan
    Commented Apr 26, 2021 at 12:50
  • @FreeMan It is for sure. If there is no white wires a.k.a. neutral, OP can not connect the switch neutral. My guess it has neutral connected inside the box because two black wires means two cables. Each has black and white wire inside at least. If there is not cable but pipes, the additional wire may be pulled inside. Only OP knows what's going on.
    – user263983
    Commented Apr 26, 2021 at 13:25

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