Problem getting 3-way working with cooper dimmers

Hi, I recently installed a new Vera3 system and started off with Cooper switches and dimmers. I am have a huge problem getting a 2-way system working. The instructions differ greatly from my scenario and I’m starting to wonder if it is even possible to get this one working without running some new wiring behind the walls. The part that stumps me is that the hot and neutral run to the light first before hitting the first box. This is how I believe it looks. I am using Cooper 9540-N as the master and 9542 as the slave. Any ideas would be greatly appreciated.

Breaker panel ---------black/hot---------light------------first switch----- -------------red-------------------------- second switch
Breaker panel ---------white/neutral----------------------first switch----- -------------white------------------------ second switch
-------------black------------------------- second switch

That Cooper model requires a neutral at the switch.

If your supposition about the wiring is correct, you do not have enough wires to install this switch. Although, you could use a switch that did not require a neutral.

Make sure that you are properly understanding your wiring. You must positively identify all wires before you begin.

I’m not sure I’m reading your picture right but I’ll take a stab and this as I just did this last week in my 80yo house. I’m not sure how your place is wired but maybe some of this description will help you troubleshoot anyway.

The not so quick summary is this: power from the breaker (or source) should come into only one of your boxes in a standard two location setup. This is where the ACCESSORY switch goes. The accessory switch doesn’t actually switch anything. It just acts as a slave to the master switch. All the accessory switch needs is power. When you wire the accessory switch, you also tie the wires together that are in this box to send power to the second box. There, the MASTER switch takes this power and actually switches the power to the light. Whatever wires you tied in the first box to the line wire (usually red and black, but in my old house everything was cloth and looked black) is where the power comes out in the second box. Now, in reality this accessory switch could be located anywhere. It controls the master by associating both switches to each other through Vera. So you could actually do this with any two switches. The wiring diagram was just trying to take a standard 2 location setup with the standard wiring. As long as both switches have power, the MASTER just needs to be located in a spot that controls the light. The accessory can be located anywhere with power. They don’t have to physically connect together.

Looking at the 9540 instructions, picture 2.3 shows the first box where the power comes in. Its the cable coming into the box in the bottom right. The black wire with the tag is the one with current. You can see the switch’s black wire is connected to it for its power, as well as a red and black from the other cable going to the second box. In the case of this setup, 3 blacks wires and a red will have constant power. Connect any whites together and and grounds as appropriate.

Picture 2.4 shows the wiring for the second box with the power coming from the first box through the tied red and black wires. They connect to the black wire from the switch. The switched load is output to the red wire from the switch, which then connects to the black wire (the one with the tag) going to the light. All of the whites get connected again as well as the grounds.

So going back to your diagram, if you don’t have a red and black wire going between the two boxes, you should have something connecting the two. The hardest part is identifying what you have. I can go through the process if you want but I’ll save the typing for now. Since my house wiring is old cloth covered, everything looked black. I had to disconnect everything and logically figure out what all the wires and cables did. One of my switches was also part of a multi gang unit so there were even more wires to contend with. Basically if you disconnect the wire that has the power, nothing else in the system at either box should have power. Now say box #1 has power and you disconnect it, but somewhere box #2 still has power. Well that’s fine - just take the box with the light and put the master there, and just wire the accessory in the other box to the power, but no need to connect the two. I guess there are multiple ways to handle this depending on what you have.