Not being sure what you are trying to do or what you are picturing above, so here goes...Was testing my ground with an old multimeter but not sure on the settings that it has as the ohms has different ones but only one moves. The setting that did work I saw 40ohms. I touched the metal and the negative but idk if thats where i need to test this. View attachment 301624
First you have one lead grounded to a painted piece of metal and I have no idea what the other end is connected to. If you want to find the resistance of say your negative ground cable, completely disconnect it from the vehicle, set the meter to ohms and place a lead on each end. Hopefully you get next to zero as that will indicate you have a good ground wire.