Verification, please?

Mattax said
IIRC, when I was looking at a '73 FSM, the Ignition on Start feeds the ECU pin through the 0.5 Ohm resistor.
I don't know why they used two pins but one possibility is they are joined internally.
In which case, during Start voltage is reduced from roughly 11 to 12 Volts by the 1/2 ohm resistor.

Almost. During 'start', available voltage (battery, through a switch, through a bunch of wire) is supplied through the 1/2 ohm or compensating resistor.

A basic ignition 2-pin ballast pic is attached. Not what you find on a '73, but the wiring in question is shown.

Mattax said
During Run, voltage is reduced from roughly 14 Volts by the 5 ohm resistor.
Just a guess.

During Run, system voltage to ECU-1 is NOT reduced. I could understand wanting to route the supply V through the resistor on Run because the voltage is higher, but that's not what happens.

There is a tie point to coil+ in the harness on the Start wire.

Italic tags get all messed up in edits. Don't know why. I don't seem to be able to fix 'em.

Mattax said

I think the best way to join stuff is with double wire in the open barrel terminal. So one methods will be to clip and replace the Packard 58 (or 56) terminals. See what they did on a '70-'72. I think the run to the Voltage regulator and alternator positive fields are splice into the wire. You may not have to touch those. If you do, a splice connector like 67Dart273 just posted about would be a good way to go.

Click to expand...

Thanks. I recalled the 'Packard' part, but not the number(s).

I ordered some Packard 58s from Mouser. The local NAPA retailer had no idea what I was after, was not familiar with the Packard number or the back clip retainer design.