roadkingrick

I have a 2015 sierra DD 1500, with bed rail lights. Id like to hook up a new canopy chmsl? #rd brake light and inside canopy lights. since i have the rail lights factory I assume I could wire the dome in and (leaving the cab switch on ) use the dome light to light up the dome and the rail lights on? Has anyone done that before? And the 3rd brake light, the post above says it may already there in the bed rail harness? Otherwise on a 2015 is there a 3rd brake light wire somewhere from factory or do you have to use a logic box and wire from trailer plug or turn signals? I could use any experience you got. Thanks