two wiring questions

[johnwaynejeep]

I have two questions about the wiring in a 74 K20.

I toned out all the pins from the instrument cluster plug to their final location in the engine bay and I'm trying to make sense of what I found.

All of my 3 pole gauges (oil, temp, fuel) had one line to a ground reference in the cab, each had a line to a specific sensor and each gauge had a line going to pin 1 on a black box mounted to the firewall. I assume this black box is the ignition module and I assume that line 1 is a voltage reference for all the gauges. Can anyone confirm this? I'm pouring through the wiring schematics that Hatzie posted up...thanks by the way...but I can't figure this one out yet.

My second question is the 4WD indicator on the dash. My cab and wiring is off a 2WD so the 4WD indicator was never installed and I can't find this in the schematics to hook it up. Can anyone tell me where the 4WD indicator gets it's source from? It's pin 14 on the back of the instrument cluster.

One piece at a time, I will rebuild this truck to good working condition. Never underestimate the power of stubborness.