I think that if you talk to experianced electrical tech/engineers you will find earthing faults are a common problem, mutiple systems can have earthing issues at the same time, especially with corrosion due to moisture ingress. Sigh!
Multiple faults
I was originally talking about all earths, not just for the battery earth that you have focused on. Were talking about the earth point to the car, not to the battery terminal. Its not just the battery that can connect to the battery earth point!
I think that if you talk to experianced electrical tech/engineers you will find earthing faults are a common problem, mutiple systems can have earthing issues at the same time, especially with corrosion due to moisture ingress. Sigh!
I think that if you talk to experianced electrical tech/engineers you will find earthing faults are a common problem, mutiple systems can have earthing issues at the same time, especially with corrosion due to moisture ingress. Sigh!
You say that I focused on the battery earth? I'd say that was you.
Perhaps you could talk to your local 'experianced electrical tech/engineer' and ask about the chances of unconnected mulitple earths suddenly going bad due to moisture ingress? Probably as good a chance as having four simultaneous tyre blow outs without driving over spikes.
By now, the OP has the answer in any case....and it isn't multiple earths or even many circuits at a single earth point.
Like you said, it was only a guess and I never meant to jump on it.
2017 Qashqai n-connecta J11b 1.6dci