Power to cluster 1973 dart
Go to MyMopar.com and download the factory 73 manual if you do not have. Wander on past the diagrams and there are depictions of the connector appearances. CE is "connector, Engine", "CI" is connector, "instrument.
PART of what you need to do is trace the panel itself. Go to the hot side of something like a warning lamp, as these have switched 12V power on one side, and the other goes through the appropriate switch to ground, AKA oil pressure switch. Once you find that, you can trace, on the PC board wherever else it goes, and back to the harness pin.
Here is the PC board connector, "CI-14" That same oval label will be on the WIRING diagram next to ANY terminal depicted that is at that connector This is from page 8-168 of the 73 Dodge manual
Now, we know we are dealing with CI-14, and now we have to think............Look below, is the junction of incoming power for the oil and brake lamps. Note also it feeds the gauge limiter. NOTE that this goes up to CI-14 in the center, the G5-20 DBL (Dark BLue) Now you will have to refer to the CI-14 diagram to see which pin that is. NOTE that the G5 wire goes to a juncton at the top left of the crop. You'll have to follow this back, but it eventually ends up at the ignition switch