hmmm auto lect tricky.... sounds like a visit to an auto sparky might be in order.

Have you run your voltmeter at the alternator outpur to see if that is outputting the correct voltage?

The only advice i can suggest to methodically work along the wiring to try and find when the volts are stopping.

I dont evny you i hate when auto sparky stuff goes awry...

Ok its been a long time since Ive been on here.

I have a datsun B210 1977 5 speed.
Charge light came on one day and wont go off.
System not charging.

Used several different batteries. Not Battery related.

Had alternator tested, GOOD, Replaced any how with re-manufactured unit. Probably not Alternator.

Replaced Voltage regulator unit.

Today went all ground connections, sanded and cleaned any corrosion i found, cleaned battery terminal and charged battery.

Re assemble, Still nothing.

I have a really high idle right now for another reason and still voltmeter at batt reads 12.40v at most.

I am Officially Stumped.

Any body have any similar experience?