I understand that you would put one lead on battery + and the other lead on that wire at the load, load the circuit and want to see s less than .5v, or do all of that on the ground wire to check that side. Can you also go from battery - to load + side, load the circuit and look to see at least 11.5v then move your lead over from load + to load - and look to see .5v?
Yes but it needs care ---- yes because all the all the voltages in the circuit must add up to the supply voltage, the but comes in because putting any load on the battery pulls down the supply voltage.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)