Oh yeah - one thing -
When you try the 12v, if it doesn’t work, just try switching the lines. I got one of those Thule license plate holders with a light (I use it on the ladder, since my plates are covered when I have the bike rack on). Put on the DTP connector and couldn’t figure out why it wasn’t working. Last ditch effort I just switched the lines (so it was red to black and black to red) and it worked fine. Beats me, but “whatevs” as the young people say. We’re all looking forward to seeing the pictures!
One last thing - lights on a moving car on the road. F?!&%#g kill joys.