[Gasoline Fumes]

I've been playing around with this too. Does the alternator actually shut off? I got the impression from my service manual that it just reduces the charging voltage to 12.5v. In other words, the battery won't be drained by running at the 12.5v mode for extended periods. I know the voltage drops fast during engine off coasting with the headlights on. I can run a lot of accessories with the 12.5v mode and the voltage seems to stay there.

I have a voltmeter in my Civic and grounding the control wire does drop it to 12.5v from 14.5v. But not always. Sometimes the alt doesn't respond and sometimes it will drop to 12.5v and then eventually jump back up to 14.5v. Have you seen anything like that or is my alternator just weird? Or does the alt have the ability to override the control wire signal?