Another erratic fuel gauge

[mbboy]

The needle on the fuel gauge of my 380sl was jumping around when the gas level went below 1/2 tank. So I assumed it was the sender, and replaced it.

However, the problem still exists, and after reading some posts in other forums, which I should have read before, I have to conclude the cause of the problem is a loose or corroded grounding wire somewhere behind the instrument cluster.

So, before I remove the cluster, I was wondering if someone could tell me which wires are grounds, how they're connected, and where they lead.

Thanks very much in advance.