So I watched several videos on YouTube showing how to replace the 12V battery, but have serious concerns about all of them, or their videography was terrible (cell-phone videos).
I produced my own video of the process showing the steps called out in the service manual, including disabling the HV battery (easy) and removing the orange connector that sits right over the 12V battery (also easy once you know how). No other video did this, so they teach you to just turn the battery on its side and pull it out.
My used C-Max, which was Ford serviced its whole life has the orange wiring harness all scratched up because the service guys were also ignoring this step. Let me know if this video works for you to get your battery removed:
