First - some history. I had an electrician install a Leviton photo sensor 3 way sensor in my laundry room about 15 years ago. He tried it in one location and couldn't get it to work. He then moved it to the other location and also had some issue, but ultimately he got it to work after me agreeing to not use the other switch (they are literally 4 feet from each other as the doors are across from each other).

Fast forward to today.

The Leviton slide thing broke off awhile ago, so while installing WeMos in other locations, I thought this would be perfect here as long as there was a neutral wire. Minimally I needed to put a normal switch back in as I was using a toothpick to turn the thing on/off/delay.

I opened up each switch location.

Leviton-photo switch - there is no neutral here. Now the interesting thing is that the guy capped off one of the wires in the box and one on the switch, apparently to get it to work.

• Also, there is electrical tape wrapped on a brown wire (is that to signal load/line?).

Non-working switch - this has a neutral wire in the box, but I'm so confused by what he did here.

• He has pigtails from the black screw and the brass screw on one side together with 2 black wires from the box - so all 4 in a single wire nut.
• He has a brown wire from the box to the other brass screw.
• Inside the box, there is yellow and brown wire in a wirenut. This yellow wire is wrapped around the brown wire from above and this brown wire.

Now, I did replace the Leviton switch with a normal 3 way to ensure I'd have some light and that works. The other switch as is still does nothing (not surprising I suppose).

So - my goal is to get the WeMo to replace the old non-working switch. So, how do I figure out which is the line/load and which are the travelers?

I will insert the pictures once I get them from my phone.

Thank you!!