I'm just about to hardwire in my dashcam but really struggled with the hieroglyphics of the fuse box diagram. Luckily, I came across this useful website which I haven't seen mentioned here yet, I think it is BMW's in-house repair manual:
https://www.newtis.info/tisv2/a/en/e89- ... s/f-fuses/
It has a bunch of info that I haven't explored, but works very well for getting fuse descriptions.
Go to the main page, select your vehicle, and then use the search function on the right and type 'fuse'. From here there is a list of what each fuse actually does. Use the below diagram to guide you toward the right fuses.
For my dash cam install, I'll be using the following:
Fuse 8 - Cigarette lighter - on w/ ignition
Fuse 77 - Interior lighting - Always on
VIOFO A129 Duo dashcam with parking guard 3 wire hardwire kit (switches from full recording down to low-frame rate recording when ignition is off).
I haven't hardwired the cam yet, so I'll come back and edit this if the car doesn't like that fuse.
Hope this helps,
Beeacon.