securing an external RV cable

I had a similar problem with the cable to my backup camera. While changing the clearance lights to Leds, I discovered raceways were built in the back wall for all the clearance light wiring and fished the wire thru those raceways. When the center clearance light was off, I made a 1/8 " al plate to go behind it that has a channel to run the power and video wires under that light. And the camera bracket is mounted to that plate. The camera power is taped into the trailer clearance lights power but the video wire runs thru the raceway at the top of the wall and down the right side to the brake light. I couldn't find a way out at the bottom of the wall so I drilled straight thru the wall at the brake light (into a storage closet) to get the video wire out.