Update: watched the video and sprung for a digital volt/ohm/amp meter. Measured the voltage this morning, shows 12.7 volts on the battery which is still disconnected. Selected the 10 amp range on the meter and got no indication when measuring between battery ground terminal and disconnected ground cable. Selected 600m range and got a reading of 24.6 milliamps. If I try to connect the ground cable to the battery it sparks as if trying to weld itself together, so I haven't tried to test the individual circuits yet. Still trying to figure out how to proceed without welding the terminal to the cable.