Tapping A Hot Light Wire

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I have a 2021 2500 Limited and I want to tap a wire that is hot when a door is opened. Such as a dome light, floor (under dash) light, or a puddle light on the rear view mirror. But only a hot when the door is opened. I may have answered my own question when I said a under dash light, I could go in search of a wire there. However, in the A-pillar there are some wires that run to the dome light for example, does anyone know of a wire anywhere and the color of that wire that I could tap. I'm may install a set of small LED's that would activate under the truck frame when the running board is deployed, turning off when the running board retracts or when the light I'm tapping into goes out.

Thanks for some ideas.