I've used a Philmore WS26 crimping tool for lots of crimps on my bike--just Google it and you will come up with some on-line vendors--bought mine at Fry's Electronics for 7.99, but that was more than a year ago.

The four wire connector under the seat/in front of the battery, is the Parts & Accessory connector. It's used for a variety of HD accessories since HD apparently doesn't want us to hack the wiring (e.g. saddlebag spoiler/LED's) on our bikes.