Elect Ign Distributor Output LOW?

Like Bewy said; the pick-up coil is just a signal generator, and neither needs nor wants to be grounded.
The P/U is a closed loop system. When the coil is excited by the moving iron reluctor vane, it generates a tiny signal voltage, that just runs around in a circle between the pick-up and the ECU, When the ECU senses it, she then fires the ignition-coil in the usual way. The pick-up does not need nor want a ground.
The electrons are created and pulsed by the moving reluctor vanes. If that wire becomes grounded, spark goes away. If the reluctor stops moving, the sparking stops. If the reluctor becomes magnetized or a vane is too far away, the signal voltage becomes weak, and, if it falls too low, the ECU will not receive or read it.
>@pishta gave a resistance reading. I have tested a few good working coils that were operating at as low as 250 ohms, and or .25VAC when spun by hand. The resistance, and thus the output voltage, seems to vary with temperature, but is a minor thing to the ECU.
>I have tested the coil with reluctor-gaps from Zero to .030 and they worked fine anywhere in that range.
> It is my opinion that those coils are extremely robust, and darn near fool-proof
> The weakest link IMO, is the that the wires from the coil to the grommet at the distributor body have to flex during the operation of the Vacuum Advance canister. Since my first Electronic-Ignition Mopar back in the 70's, I have only ever lost 2 pick-ups both due to one of those wires failing.
>I have seen at least two or three pickups, and they are coded by the wire colors, and are directional as to which way the reluctor spins. If you swap colors you can set the idle-timing and it will run; BUT the engine will not take rpm very well, and a timing light will strobe in random and unusual ways.
>The Small block P/U has one Orange wire. The P-up from a lean burn has a gray wire. And the other one I have seen had IIRC a violet wire.

I honestly think you are looking in the wrong place, as there is NO JUICE coming from the ECU into that pick-up; she is a stand-alone signal generator, and the ECU is not particularly interested in anything about that signal, other than it rises above a threshold level for her to see.
The thing I find odd is that when you replace the pick-up, something changes enough that for a time, she runs normally again, even tho the ECU was not tampered with. Since it has happened more than once, that's a poser.
BTW
1) for testing purposes I have plugged in any ECU from any of my
other Mopars, and it worked fine
2) the dual-ballast is two different-spec ballasts on one platform; one side reduces the running voltage to the ECU, and the otherside reduces the running voltage to the Ignition coil. Don't mix them up. Your engine will run fine when the ballast is cold. Less fine as the ballast heats up. Do not run a 5-pin ECU on full-time charging voltage.
EDIT: see post 20. Just cuz I haven't seen that, doesn't mean it can't happen, lol. Moisture intrusion is a problem for all electrics, so OP, keep your eyes open for it.