1977 wiring help

[1marteck]

I am working with a 1977 Bronco harness from a junkyard that has been cut at firewall on both sides.
I have one 14 gauge wire with a green tracer it’s continuous using an ohmmeter from left to right. I have no idea what this wire is for and where it actually goes inside the instrument panel. Any help would be appreciated

 

[Crush]

I believe the green wire goes to the coil and that is where you get the signal for a tach. But i cant for the life of me remember where it connects to on the dash?

 

[DirtDonk]

What color is that wire?
Black with a green trace is a general accessory wire, but it’s usually a little larger gauge. There’s a red wire with a green trace that is for the ignition coil positive.
But there should be a secondary one of the same color that’s for the ignition control module as well.
There are at least three locations where the wire harness passes through the firewall. Do you have all three sections?

 

[Oldtimer]

Looking at seabiscuit68's drawing the only yellow/green wire is horn.

 

[Quick & Dirty]

Horn would make sense, as the relay is near the battery, but the horn is on the drivers side of the core support. Everything crossed over through the dash rather than just crossing the core support.