Smart Fan/Light Dimmer Switch - switch powers on but not to fan/light

[Nuzz54]

Hello! I am trying to install a smart fan/light dimmer combo switch (Treat life). I have installed one of these before in another location of the house with zero issues so I didn't think doing another one in another spot in the house would be an issue for me. I full well know which are my fan load, light load, hot load, ground, and neutral wires from the previous connections of the current fan/light dimmer switch (I currently have a regular old Lutron dual fan dimmer and light dimmer switch). I hooked everything up properly according to the below wiring diagram, and the switch itself powers up with no issue and even connects to my Wi-Fi (I assume via power from the neutral).
- manufacturer's wiring diagram.

Problem is, the power doesn't go anywhere. The fan/light does not turn on, and even knocks out two other lights on the circuit. Now, I know these smart switches state that it cannot be used in a 3-way switch application and has to be single pole only, which my fan/light is in fact single pole. There is no other switch in another location that controls the fan. However, one of the other switches in the same gang box and circuit, is in fact a 3-way switch as it controls my hallway light and there is another switch in another location for this. Is this what is messing up the power here? Is there any way I am going to be able to work around this? I have installed a regular 3-way light switches before but admit that once we enter 3-way territory I start to get confused and takes me a few runs with trial and error to get it right. My hunch is this has to be the reason as I can't figure what else could possibly be wrong here. I've checked all of my connections many times over. Any insight is greatly appreciated!

- photo of gang box. the light switch on the left is the 3-way that loses power, this middle switch is a regular single-pole that actually does maintain power, and the right is the newly connected smart switch that is not powering the fan/light but does have power itself (disregard the neutral not being connected, I took the photo after I started disassembling again, sorry for confusion. The neutral does give power to the smart switch only as stated above).

 

[Avo Mk8]

I can't see that having other 3-way switches there in the box is anything to do with your problem, if they do not form part of the fan circuit you are changing.
There is a group of what I take to be neutrals connected together at the bottom of the box, and if the neutral of your fan went there originally too, then surely the white dangling neutrals (that you mention disconnected temporarily) in the photo need not only to be connected together, but also to that other group? Maybe they are, but I can't see that clearly in the photo.

 

[Nuzz54]

I can't see that having other 3-way switches there in the box is anything to do with your problem, if they do not form part of the fan circuit you are changing.
There is a group of what I take to be neutrals connected together at the bottom of the box, and if the neutral of your fan went there originally too, then surely the white dangling neutrals (that you mention disconnected temporarily) in the photo need not only to be connected together, but also to that other group? Maybe they are, but I can't see that clearly in the photo.

Thanks for the response. There weren't any neutrals in use before, even on my old fan/light dimmer switch. I grabbed a neutral from the bundle for this new smart switch. I agree I didn't think a different 3-way switch unrelated to the fan would affect this, but I don't know what else could be the problem!

 

[Nuzz54]

Well, in case anyone is curious or has a similar problem in the future, I figured it out. Instead of grabbing a neutral wire from the bundle in the box, instead I took the neutral pigtail from the switch and added it to the bundle, with a wire nut encapsulating all of the neutrals. This worked because it maintained power to all of the neutrals in the circuit I suppose.