[steven114]

I can't help you on your servo problems, but when you're checking for a conducting path between your frame and electrical system, it's probably better to use the "continuity" setting on your multimeter, or at least measure resistance instead of voltage difference. If your frame is isolated, as it should be, the potential difference between that and the electrical system could be almost anything (correct me if I'm wrong there) but the resistance should be effectively infinite (usually displays as a 1 in the leftmost column on the multimeter).