Which wire are you using? There are three. Count them like this. 1 - 2 - 3 - empty
The #1, the only outside wire is 12V persistent. The middle #2, we don't use. The #3 is black, its ground.
The #1 has been reported to be different colors, so we can't tell you for certain its color. Although #3 is black.
Try that.
As for fuses, I've seen to different spots in the fuse box reported as the fuse. Both #50 and #100. I don't know what's correct. Could be depend on year of car. However, it does not matter to me, because I am putting an inline fuse on the camera anyway (always).