You can goto autozone or any parts store and get an external barrel type fuse holder with two wires hanging out for a few bucks. get two alligator clips on the wire ends and use this as your bypass. That way you are protected, and can jack right in without having to cut any wires or make any modifications to stuff, hopefully.
On those type of fuse holders, you *might* be able to push the wires from the outside of the fuse holder, to the inside of it, basically sliding the plastic container back, exposing the contacts (you may find the spring side, the spring is soldered to the wire or something like that) and then just hook your jumper to it like that, this will also allow you to examine the holder for any issues. Remember with low voltages, it does not take much crud at all, to wreck a connection. The slightest rust, green, blue, brown on the pad end and it won't work, or can over heat and melt.
Aaron