The backup switch for non Powerwall installs is not the same. You have all the hardware you already need, if you have a functioning powerwall install, have a wall connector and the main charger used for the truck is backed up.
Once installed the light can be turned on or off from either the primary outlets and mods vehicle view or by scrolling down for the more integrated controls. (Off/Ditch/etc) And a brightness control.
Just to add to the chorus here, I had mine installed this week. They will basically do the bulk of the work, minus removing the black tape covering the light and making the final connection.
On the final connection -- the wiring harness in the b pillar -- you literally need to snap the power...
I too have a CHAdeMO adapter from my early Model S days. Haven't used it that often but it did help me out of a bind a couple of times on long distance trips where the only fast charging that was working was a CHAdeMO unit. Unfortunately, the adapter requires frequent firmware updates for...