Another "taco plate" question, Update: job complete, but is gauge accurate? Options

[Cevan]

I have '75 1.8 that the PO installed a nice center console complete with gauges. The volt meter works, clock didn't until I pulled it out and found the ground wire disconnnected. Now it keeps perfect time.

There is a plate currently where the oil temp sending unit goes. I also have a oil temp sending unit. I believe the order of installation is the red o-ring, the sending unit itself, the gasket and then black cover. I'm assuming I ground the black cover and the lead from the gauge goes to the sending unit.

I can't seem to locate that wire. I'm assuming that the oil temp lead goes thru the center tunnel into the engine compartment. Where should I look? Will a ground wire also be with it? What color should the wires be? Brown=ground?

[Spoke]

I added an oil temp gauge in my 71 and found that a wire did exist in the interior that went to the relay board. I didn't think 71's even had the center console. The wire was under the shifter carpet right by the shifter. After looking through the schematic, the wire was for a temperature sender. I think the wire was brown.

The wire continued across the relay board to the engine connector but the connector to the engine did not have a wire at that position. So I grabbed an extra engine wire harness and pulled a contact out and wired from engine connector to taco plate.

Spoke