I’m trying to install a 12724 dimmer switch along with two 12723 add-on switches in a circuit that’s connected to 3 different ceiling lights. I believe I have everything wired correctly, and the two end switches (12724 at one end and 12723 at another) both are working correctly. The switch that’s at the 4-way location doesn’t do anything, however. In that box there are 2 twisted whites in the back of the box, two black, two red, and ground. I did the same that I had done with the other add-on switch and twisted the blacks together, put a jumper on the neutrals in the back of the box to the switch, and connected the two red travelers to the switch, along with ground.
In troubleshooting, I disconnected all wires at the 4-way location and only the main dimmer switch then had the blue light on it, but no lights or switches worked (as expected). Once I connected the two blacks together in the 4-way box, the main switch worked to control the light, but the other aux switch did not work (as expected with travelers not connected at the 4-way). Once the reds were connected, both the main and other aux switch worked, but the one at the 4 way still doesn’t. Any ideas on what could be the issue? It’s a brand new house if that helps with wiring possibilites.