Thanks for the helpful feedback sounds like mine isn't the only one to cause problems.
Originally Posted by 68tpls400
Push in, twist to lock. If the plastic is worn, they may not stay in.
I wonder if there's more than type? Mine doesn't look like you can twist it to lock. The socket has a single location tab which fits into a notch in the tail lamp housing. *** see pics *** Once inserted it doesn't twist. The other plastic tabs don't do much either. Maybe they've just been bent in over the years. Or maybe the two metal grounding tabs should hold it....