I just recently acquired a speedo for a 280z. I think everyone that owns a 280 knows what the backside of the speedo looks like. The green connector, shown in the pic, shows it unplugged. I believe it is for the BCDD but I'm not 100% sure. I found it in the schematic but its not clear to me because it doesn't show it as a separate connector. Can anyone verify it is for the BCDD?

 

well if it plugs into that little box then its the BCDD for sure.

It does actually. I should have given it another look, would have seen the wires for the connector coming from the "box" . My wife told me the other day that I am blind as a bat, lol.

So I guess that would be a good way to disable the BCDD if it were giving someone a problem right?

Not sure about that, the BCDD is disabled by going under 10 mph. I cant recall if you have to turn it on or off to disable. Next time I take mine out I will pull the plug at the BCDD valve and see what happens.

I've done that before, just don't recall any change. So I left it plugged in. 

Curiosity got the best of me when I saw the green connector disconnected. That's all.  

As previously mentioned, it's for the BCDD.

The BCDD is active when there is no signal supplied to it. so with that connector disconnected, the BCDD will be active at all times.

Of course, depending on how you have the BCDD mechanically adjusted, there might not be any difference whether it's activated or not.

12 hours ago, Captain Obvious said:

depending on how you have the BCDD mechanically adjusted, there might not be any difference

True, and I do have it adjusted "down" so it doesn't hold the idle up as long as it used to.