I believe that would be referring to the wheel well light, lights in the equipment compartments (not yet modelled), and so on. Not just one switch.
The checklists provided are an almost exact facsimile of a real world operator’s, for authenticity they haven’t been customised for the in-sim world.
I’m sorry to hear that, but as it’s not related to the Challenger I’ve moved this post.
This crash looks to be caused by the core sim and you should get in touch Laminar if it’s persistent. https://www.x-plane.com/support/
Anything you set it to other than 0 will be reset back to 0 on the next frame by the sim, but the result is the lighting cubemap gets rebuilt immediately. There’s a discussion on the “Dev Slack,” but there was originally some confusion as to the exact dataref name that got implement in the sim a couple of versions ago.
The Honeycomb has at least one other axis you could assign to Nose wheel steering, if I recall. If not, there’s probably a way to use the keyboard, assuming you don’t have rudder pedals.