Does anyone know specifically which fuse is for the 12v plug that's on the dash? This is for my 2018.

Planning on using an add a fuse to wire up a new accessory and going to extend the time on forscan.

These 4 micro fuses all show vehicle power and I'd assume it's one of these 4.

 

In 2018 Owner Manual page 334.
Fuse #6 20 amp & #8 20 amp are Power Point 1 and 2, in Engine Bay distribution box.
Page 336 #51 20 amp for Pwr Pt. 3.
Good luck.