(Feb. 6, 2022)
Finally! Time to jam everything together!
Nothing powered on! This was devastating. All my work might be shot! Did I short something out again? I checked the battery output voltage with a multimeter and it was definitely okay. I also tried powering up the controller box with just a power supply. Oddly, it drew no current. Maybe there's a fuse in the controller that blew?
In the midst of all this plugging and unplugging, I found my problem: the Andersen connectors I had attached to the control box had come loose!
Fortunately I was able to snap the contacts back into place. I'll probably want to epoxy those up in the future.
With the connections checked out (I was able to engage the headlight by by holding the up button and engage the motor by holding the down button), I packed everything into the battery's controller pod:
And then mount the the pod's outer panel back on:
And reattach the seat for a look at the final assembly!