Installing Dimmer w/Pico - unique wiring

Hi, ok pretty new to this, so basic explanations/information would be much appreciated. Cannot for the life of me figure out the wiring combination here. I've done a couple other dimmers which are fine.I'm trying to install the CASETA DIMMER with PICO remote into a 3-WAY SWITCH configuration.Behind door #1:1 black (common/hot) wire - was connected to common terminal on switch1 red wire - was connected to a terminal on the switch1 white wire - was connected to a terminal on the switch1 ground - connected to the box, no issue there.Behind door #21 black (common/hot) + tied to it is a wire for another light in the house. I'm assuming these two will stay together to power the other circuit in series.1 black - separate, was on another terminal on the switch1 red - was connected to a terminal on the switchwhite... there are some capped together in the back of the box, they weren't on the original 3-way switchall ground wires tied off to the boxIdeally I'd like to have the dimmer on Door/location #1 and the pico switch on #2.No matter how I connect these I tend to get no power to the light/switch, OR, the light turns on but it's only 50% power/brightness, and the switch doesn't work to turn it on or off at all.PLEASE help, been at this for wayyyy too long.

3-way switches are basically A/B switches. Power comes in at one end (common terminal) and connects to traveler A or B. At the other end, power comes in on traveler A or B and goes out to the light (switch leg) via the common terminal. In some cases, both the power and switch leg are at the same end. They will relay power or the switch leg to the other end. It appears from your description that they are relaying the switch leg (the wires capped in the back of the box). Because they took one of the travelers for the relay they used the white as a traveler (not a neutral).

If you are trying to use a mechanical switch with a Caseta dimmer, only the PD-10NXD supports this. Otherwise you have to use Pico remotes.

Because of the way your system is wired, the Caseta dimmer has to go at Door#2. You will need to find the switch leg (capped?) and connect it to the dimmer. You need to send power to the other end (black?), through the switch and back (red?), and connect it to the blue led/terminal.

Honestly, for the price of a $25 pico and a $10 mounting plate, I would put the Pico at door#1 and have full control.

Thank you! You were dead on about the white wire being a traveller, or some sort or weird wiring colours. I ended up capping all the wires behind Door #2 together, which livened them all up but that was fine. I capped the red "traveller" on Door #1 because even after capping the wires on the other end, nothing happened, so I capped it to be safe. Then at Door #1 I tied the black to dimmer, and white to dimmer. Worked like a charm! I put a Pico on Door #2 to end my misery fighting with the switches!

Awesome! Contrary to popular theory, sometimes the easy way is the best.