Oil Pressure Sender - Wiring Diagram Question?

[Futo_gt86]

Morning,

I am installing some gauges, one of which is oil press with one of these senders

http://www.ae86drivingclub.com.au/dcimages/7/7/7/6/505142.jpg (http://imageshack.us/photo/my-images/694/a100n0002f.jpg/)


Now came with this diagram

http://www.ae86drivingclub.com.au/dcimages/7/7/7/6/505143.jpg (http://imageshack.us/photo/my-images/21/img0022vl.jpg/)

G is signal wire to gauge.
WK is warning light/buzzer.
This much is straight forward.
Now there is also a green wire that comes from gauge...I'm looking at the diagram thinking it is telling me to attach/soldier green wire to the body of the sender?
WTF, seriously, am I potato retard or is this correct?
So I take it it earths through the body of the sender, but can't I just earth that wire to any common -ve?

[Matt]

You're over thnking it... attach the green wire to the top knob.

You'll find the guage also needs ignition power too of some sort and most likely a light too.

[Futo_gt86]

Yeah, I tend to do that.
I just think that wiring diagram needs to be a bit more accurate...I mean FFS why draw it like that?
I have power and parker illumination sorted.
Gauge has low oil pressure light on it, I understand it now, thanks Matt!