The key circuit has two ignition power outputs. With key in the "run" position the "run" or IGN1 contact feeds power out through the bulkhead, (normally dark blue) to the VR, to the alternator field on 70/ later, electric choke if used, and some smog doo dads on later models AND THE ballast resistor. THIS POWER GOES COLD IN START position
In "start" the bypass IGN2 circuit (normally brown) is now active as is the (normally yellow) "start" wire. The brown goes to the coil+ side of the ballast resistor, and is the ONLY power to the ignition during "start." The box gets power during this time "backfeeding" through the coil resistor to the ECU box.
Hook a light or preferably a meter to the coil + and ground. Turn key to run. You should have somewhere between 6--10V because of the drop through the resistor. Now crank the engine, and while doing so, read the meter, and you should now have "same voltage as battery" at coil + because the brown should now be feeding "full battery" power to the coil
If not, check at the ignition switch connector at the column, at the brown and blue through the bulkhead connector.
