How to do a Basic Wire Splice

I get mine at my local hardware. I would think any "good" parts house would have it.

A can of it goes a loooong way.

I like it because it turns into a rubbery type of seal, couple that with the heat shrink and it does a pretty good job. When using the heat shrink over it, I always make sure the shrink tube extends beyond the liquid tape so that it actually seals to the wire casing instead of the liquid tape. When applying the liquid tape, I cover the exposed wire completely and extend it about a 1/4 inch onto the insulator. Let it dry and then proceed with the heat shrink. And if you feel the need, you can add a dab of the liquid tape to the ends of the heat shrink tube after it has been shrunk.

I discovered it when I was running several plow trucks and had to seal wire connections going to my external utility lights, and salter on the back. The road salt in the winter was terrible for causing the connections to turn green and corrode.