I found an empty cavity in the fuse panel and put a fuse in that cavity and used the output wire from the wiring harness.... or I've used a simple wire that hot when the switch is on... and used a relay that fused to run an accessory.... most of the unused cavities in the fuse panel are light wires.... under 5 amps.... if your camera needs are under that.... I use that cavity... if they are more than that... I'd use the relay to power it up....