I am installing a Kenwood DMX series head unit that has a dash cam port. While I have the dash open I am installing the compatible camera that connects to the back of the head unit (and not a USB/cigarette lighter adapter). Everything else quick-connected with the Crutchfield pre-wired harness, but the camera requires red+black+yellow connections to switched power, ground, and always on power. I have an existing tap for the red and black wires, but not the yellow. I thought tapping the clock right over the radio would be a good option, but it appears to be part of an assembly I do not want to cut open. Interior lights might be another option but those wires are not nearby. Is there a conventional place to pull power for that yellow wire? I did not notice any other wiring into the back of the head unit that may be suitable.