Just go to your local hardware shop (Home Depot, Lowes, Ace) They should have them. Just ask the clerk for
"18 gauge wire taps" and they will show you. They're basically plastic clips with a metal blade in them. You put the current wire on one side, and your splice wire on the other, press the blade down onto them, and close the cap. Done! No shrink wrap needed, and no soldiering needed.
