Voltage problems, cutting out when hot
It seems like your your throwing darts.
I understand you are seeing power in odd places. So figure out what is connected to what and make corrections as needed.
My suggestion is get out your '74 manual, and either on the computer or some paper, draw the circuits you are working on.
Make an extra copy and mark up what you find on your car.
Then instead of red, yellow, white; you can call them by what they do.
I'd start with the power feed to the ignition switch.
This is the only one that should have power in it when the battery is connected. If anything else going to the steering column has power in it, stop and figure out why.
On the switch side of the connector, you don't need power to figure out what goes where. Just use continuity. Once everything is going to the correct place ,then and only then, look for resistance. (That's voltage drops when current is flowing. And what 67Dart273 is telling you is that small current won't reveal a moderate resistance.)
So for the '73 diagram, the column switch connector is CI 5, and power is supplied by the 12 gage red wire.
In the '73 diagram, it looks like M16 could be hot all the time as well.
If J1 is the only terminal with power, then go to the other half of the connector and make sure there is no continuity between 12 gage Red and any other termninal.
Then turn the switch to Start, and there should be continity between 12 Red and 12 Yellow and 12 Brown, and no other terminals. Then check Run.
Keep going.
Look at your '74 book and draw out what you need in a way that you can read what each does and connects to.
The factory diagrams were intended to have all the info, and the techs were expected to pull out what was needed to make a schematic. I don't know how jobs like that got billed! But IMO that's what you got to do.
It seems like your your throwing darts.
I understand you are seeing power in odd places. So figure out what is connected to what and make corrections as needed.
My suggestion is get out your '74 manual, and either on the computer or some paper, draw the circuits you are working on.
Make an extra copy and mark up what you find on your car.
Then instead of red, yellow, white; you can call them by what they do.
I'd start with the power feed to the ignition switch.
This is the only one that should have power in it when the battery is connected. If anything else going to the steering column has power in it, stop and figure out why.
On the switch side of the connector, you don't need power to figure out what goes where. Just use continuity. Once everything is going to the correct place ,then and only then, look for resistance. (That's voltage drops when current is flowing. And what 67Dart273 is telling you is that small current won't reveal a moderate resistance.)
So for the '73 diagram, the column switch connector is CI 5, and power is supplied by the 12 gage red wire.
In the '73 diagram, it looks like M16 could be hot all the time as well.
If J1 is the only terminal with power, then go to the other half of the connector and make sure there is no continuity between 12 gage Red and any other termninal.
Then turn the switch to Start, and there should be continity between 12 Red and 12 Yellow and 12 Brown, and no other terminals. Then check Run.
Keep going.
Look at your '74 book and draw out what you need in a way that you can read what each does and connects to.
The factory diagrams were intended to have all the info, and the techs were expected to pull out what was needed to make a schematic. I don't know how jobs like that got billed! But IMO that's what you got to do.