I need to replace a trailer tail light, and want to make the connections so that water will not cause any issues with the splice connections. What is the best stuff to use? Thanks

Sealed connectors, I like the ones that have a little solder bulb in the middle. You can get them at fastnel or I found a place in S FL that has good prices. Let me see if I can ring them.

You can buy the shrink connectors as Advance Auto or anywhere like that now; even Wal*Mart. But you need to have a heat gun, or be very careful applying heat with a torch a slight distance away.

Just make sure you get the heat shrinks with adhesive in them. When you heat them they will make a water proof connection. Also make sure the wires are clean so the adhesive sticks to the insulation. I work for a electric utility. We also take sand paper to scuff up the wire insulation so the glue really seals and has something to grab to. Many of our splices are completely submerged under water 100% of the time and should last many year's without issues. I am very OCD about my items, especially wiring. 😁

NAPA has them too.

A million online stores have them.

I use hundreds or more a year,

I use a lighter if someone has my mini torch.

Lighter does the trick, when there's no fuel vapors around of course.

On trailers I found grease caps work great. Easy to use and last for years. Buy them at any electrical supply.

The lights on our trailer are sealed -- went to AutoZone bought a replacement and the connectors are watertight- with some type of grease around them -- work beautiful. Not sure about older style blub arrangements.

I found a kit that has the water tight heat shrink with crimp, as well as connectors with the solder, glue and shrink tubing that use heat. I will see what works best on my bench before I make the repair. Unfortunately, the grease caps would not work in my application. Thanks for the help

Nice. Where?