I dont blame the service rep- they dont cut and splice. My current service rep would just smile and say "yeah, I figured you'd do that" (whereas a service rep there form years go would probably say "you know that voids your warranty...dick)

Oh, without a schematic how will your electronics guy know it is done properly?

Finally, did you cut ONE wire at a time...and/or have the battery disconnected when you cut the wires? Shorting out stuff is an excellent way to fry things....