I had a similar problem with my 1981 Cutlass. After removing one fuse at a time, I discovered the power antenna was cycling trying to extend but was stuck in down position. I was able to pull it up a little & it extended to full mast. No more draw & dead battery. Disconnected the power feature.
Or the glove compartment light and in the case on my car it was a faulty cigarette/cigar lighter base that was shorting out and almost lead to an interior fire. Many of the 70 cars have a map light in the rearview mirror. My 70 also had a light in the ashtray that was barely visible but probably would not draw 6.2 A
I'll check out the cigarette lighter but doubt that any of the interior lights could draw over 6 amps of current. Thanks for the idea.
The Alternator could easily draw that . Try just unplugging it 2 wire plug and if that doesn't stop the drain disconnect the main wire .
I've replaced the dashboard ignition switch in my 1980 chevy van twice, done the one in my 67 once. I'd start at the switch if it's the stock one from 50 years ago.
Alternator diode shorted only when the motor is turned off with the alternator pulley position in just the right (wrong) position.
Very strange, but at least you found something. I have never even heard of such a thing. How in the world did you find it?
I noticed that sometimes, rarely, the gen idiot lights on the dash would be on very, very dimly. When it was on I could measure current going out of the battery of about 6 amps. If I would start the engine and turn it off, the light will not be on and no current being drawn. It is a very strange issue, I agree. The light only comes on maybe once out of 10 or 20 times when the motor is turned off.
