So I’m trying to run halos on my sedan taillights and was planning on painting the housing black as well. I know how to access the main component of the headlight through cutting, but does anyone know if there’s a way to cut open the little reverse taillight portion without damaging the lens or anything important?

 

Sorry Op, don’t have an answer for you. But I think this has been a challenge for others with similar projects, and I’ve seen folks instead add a tint/film to the outside of that section (picking a shade that comes to a close enough match)

 

Could try using a hotknife to cut it open. I have seen people use that before for head lights and tail lights.

 

with sedans the reverse portion is a separate housing that you can get replacements for about $100 for the pair. I'd contemplated just keeping the outer lens and mounting studs and replacing the entire inner lens assembly with an LED COB board (flat LED chips). That's a thought. The reflective red IIRC is part of the plastic of the housing so even if you were to paint the inside black it would still be red-tinged (although that may look quite nice, if you can match it with the actual tail lights)