Battery Vampire, My generator light stays on after I turn the engine off and remove the key Options

[Deusexmachina77]

I just had my engine rebuilt.

Drove the car once for 40 miles, and it was fine. The next drive was at night with all my lights working.

The following day I try to start the car, and the battery was dead. I noticed a faint light from the generator's idiot light bulb. At first, I thought it might be a sun reflection.

I removed the cables and charged the battery. I started the car, idled nicely, cleared the ground cable, and it died immediately.

I have a new voltage regulator installed as part of the rebuild.

I do not know my next step.
How do I diagnose what is back-feeding the idiot light?
I need a step-by-step guide for idiots.

p.s. I checked the bulb to ensure it was a 12V, not an LED installed by the PO.

[kerensky]

Speaking of bad alternator diodes, it used to be common practice to test whether an alternator was working by simply disconnecting the battery while the car is running. Unfortunately this isn't a good idea with 914s, had a shop do that and it burned out the diodes in my alternator, which led to a chain reaction of other issues that eventually led to me putting her in storage back in 1986. Don't be me. (IMG:style_emoticons/default/wink.gif)