Grab the set of wires that come off the white plug towards the top. Seems a bit opposite from conventional logic but the door switches are self grounding.

No Power Constant Orange Wire Courtesy Lights Not Working
How to wire courtesy lights. Underneath the drivers side dash directly behind he parking brake is a computer box with 5 6 different color plugs coming off it. So you wire this reverse. More than that can allow the wire to melt before the fuse pops. These are cheap and available at your local parts store. Michael manning explains the install process of the courtesy dash and dome lights of our classic update kits. Dome courtesy light wiring install.
Door courtesy light install part 2 of 2 diycarmodz duration. Armed with my trusty multimeter i have checked the door switch is good and that it is getting a good ground when screwed into. How to install single din stereo in square body c10. Car modz 29423 views. Just remember with small led light strips and bars use a small fuse like a 5 or 10. In the harness will be a solid grey wire thats your interior lights t in to it and that wire is the wire you want.
They do work when you switch them to the always on position and i know i have 12v and a good permanent ground to the cars roof. Driver side light ground the the bluewhite wire and the passanger side light ground to the brownwhite wire. Typically an easy way to tape the courtesy light power circuit is right behind the courtesy light itself. My courtesy lights dont light when the doors open. In your case there is only 1 courtesy light supplied by a 5 amp breaker so in my opinion you can add up to 6 led strips and still remain below 80 current draw of the breaker rating. It allows you to plug directly into the fuse panel replace the existing fuse and add a second fuse for what you are wiring up.