more E30 speedo/odo questions

[Drew Mouton <drew@xxxxxxxxx>]

Hello All,

I've recently been working on the replacement of my primary gauge cluster 
('87 325iC) and I'm still a bit confused about what's going on behind the 
dash.

Specifically, my cluster is basically good but the odo isn't working (a 
fairly common prob). Bimmerworld sent me a replacement that turned out 
bad (which I'm sure they'll replace). Meanwhile I'm not totally confident 
that my troubleshooting is everything it should be.

Bentley says the cluster has three primary harness plugs - mine does: 
yellow, blue and white. But mine also has a fourth, green, mounted approx 
on the back of the speedo. 

In the dash, there are also a pair of loose single wires, blue with 
yellow stripe, with small couplers that let them hook into a couple spots 
of the green harness plug in the cluster. But I don't have any idea what 
they do. When I first pulled the cluster these two wires were not 
connected.

The wiring diags I have haven't helped me trace what these two wires do 
either.

Relatedly, I'm trying to avoid the appearance of a roll-back on this car, 
and it looks like Bimmerworld wants to send me a cluster with many fewer 
miles than my last reported mileage. Can somebody tell me how to do a 
'roll-forward?'

Thanks all.

Drew

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