I'm chasing a charging circuit problem. When I turn on the master switch, in car and external voltage meters show 12.5 volts. Turn on the ignition, voltage drops to 11 volts. When I start the engine, the voltage remains the same, so the altenator is not charging and the battery is draining.

I have replaced the alternator, and the voltage regulator. I then checked the continuity of the wires from the field terminals on the alternator to the voltage regulator plug. One tested ok after moving the probe aroud a while, but I could not get any continuity on the other wire. So I am replacing the voltage regulator plug. Grounds are all good - brand new cables.

Any tips?