Disclaimer: DO NOT TRY THIS (Go to your dealer to resolve any issue with your car involving malfunctioning equipment).
There are times when I might want to "reboot" the electronics on my Ford Fusion Hybrid (2017). The 12V battery is in the trunk (see picture). Under the hood are (+) and (-) "prongs", specified by Ford (in the manual) to be used to jump the car (page 229). This is needed since you can't open the trunk of your car without the 12V battery -- which is in trunk(!). Explain that to your old man.
What is the best way to disconnect your 12V battery? I did it by loosening the nut labeled "A - Negative Side" on the photo. The "washer" under the nut made an unsettling "crackle" sound (as it formed a circuit on and off a few times -- was I"frying something"?) This worked. The car was disconnected from 12V and solved a problem.
Attached are some reference 12V battery pictures from my 2017 FFH.
Edited by stlouisgeorge, 07 October 2017 - 12:58 PM.