I took power for the reverse lights and ground off of the 7 pin trailer harness back by the bumper. Then I ran the positive wire up along the frame rail with my A/V cable in a wire loom to signal the radio when the truck was in reverse. Little extra wire but I was running the A/V wire anyway and I didn't have to worry about tapping in under the dash. I made the camera only powered when the truck was in reverse. I know some guys might like it hot all the time or on a switch to be able to power it so they can see behind them while they are driving with trailers and such.