Battery light stays on, even with key out

[wikkid]

As soon as I hooked up a new battery, the dash's red battery light lit up, and the key was not even in the ignition. I am still working on getting the car to start, so I don't know yet if the light will go off as normal when the car is running. When I put the key in, the light stays on, as if it were normal, but if I take the key out again, the light remains on. So now, until I get this worked out, I leave the negative battery lead unhooked most of the time, as I work on the car or when it sits for a couple of days in between work sessions.

Any clue as to why it would light up without the key inserted?

[mdrburchette]

Possible electrical current from the battery bleeding back to the alternator through the field coil wire? Pull the field coil at the alternator and see if the light goes out, then check for voltage at that wire. You may have a bad diode in the alternator.

[wikkid]

Hmmm... perhaps this is why there was a 65-amp Bosch lump in the passenger seat of the little beast when I took possession......