I, ... uhm... purchased the splices from work. You can buy similar splices from a hardware store. The look almost like a conventional butt splice, but the outer insulation is heat shrink and the inside of the insulation is lined with a wax like substance that seals the splice when you shrink it. Ace Hardware carries them around here. The RayChem splices are kind of a speciality item used in aviation. They also require a special crimping tool. Someone on the TDR or rv.net (can't remember for sure) posted a link to a 7 pin extension harness that had all 7 of the wires connected and therefore did not need any splicing. I think it even came with the in-bed 7 pin connector.