I often have lunch with the truck drivers who work out of the depot over the road. In conversation, they talk a lot about lights, and oils, and how RV drivers treat truckers with a lot more respect on the road since they know what they're going through.
It seems that some of these lights will start working properly again if left to dry out in the sun. Also, when they do not have sealed covers, they drop a packet of silica gel inside the back of them, then seal them up with silicone. There's also a guy who collects partially failed reverse light LEDs and is making a "light ceiling" in his workshop from them. He waxes lyrical about how he's got the brightest workshop in town, and it draws two amps.
That's the thing with RVers - we talk to strangers. I think it's part of our make-up.