12v vehicle question - identifying earths in main loom

[gazmatic]

hi all, i am trying to locate earth wires in a main vehicle loom (12v) of approx 40 wires

the car has the battery connected at the moment and there will be lives, earths, etc throughout the loom.

if i check continuity from the ground (body) to each wire itself (via a needle prick multimeter tester), to determine a link to ground, will this cause any issues with potentially having the meter on body ground at one end, and potentially then tapping into a 12v live at the other probe? would this cause a short or does the multimeter prevent any issues like this? (and the vehicle canbus / modules itself potentially being affected?)

or is there a better way to check for earths whilst the battery remains connected? disconnecting it will mean settings get lost so trying to avoid that.

cheers

 

[Geoff1946]

The car probably has a standard colour code for earth wires. Locate one of the earthing points, usually found (e.g.) near light clusters, especially in the boot, under the dashboard, near the fuse box, etc. If you can find one, and all the wires are the same colour that's the answer to your question. Alternatively, if you can locate one of the almost indecipherable wiring diagrams, from a Haynes manual or similar, that should tell you. Probing wires won't work as many load supplying wires will appear to be ground when not powered.

 

[poni]

what are you trying to fix or fit into your car?