Why not use RGBW or plain RGB led's and strips.
Use a RF remote and you can control the color on the fly to all of your lights.
Use old Cat 5 cable and
JST plugs. Rip out the wires and use it to connect all the various "modules" aka switches to 2 or even one RGBW LED control box.
Want green today? press green button. want red? etc...
Very simple to do.
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This setup allows for multiple zones. controlled viia one remote.
Zone one, doors.
Zone two, all dash.
Zone three, overhead lights.
Zone four, under body, under dash, under seats, etc..
RF RGBW controllers and remote
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Single zone controllers.
RGB RF controller
better RF RGB controller.
heat shrink tubing
RGBW Led stip
RGB Led Strip