Many of my marker lights have those little plastic tabs broken off that hold the metal that secures the bulbs and makes the connection. I bought some new lights to replace the really nasty ones, but was kind of ticked off that the ones that were in good shape visually, had the plastic tabs pull through.
So, with my Makita cordless and a tiny little drill bit, gently drilled a hole and tightened down a small sheet metal screw. Problem solved!!! Took all of 5 minutes.
I noticed that the interiors of these lights get wet and grimy. So I tried wrapping the perimeter a few times around with teflon tape. It really made the lens snug, and probably a lot more waterproof.
That's my new found tip of the day!