[malim]

Thanks guys for the info. I've taken this last altenator and had it checked by 5 different autoparts houses and they all came up with the same conclusion - is't a good altenator. I don't think the ignition switch is bad because the charge light comes on when in the run position and the engine is not running. also I put a 10 ohm resistor from the battery lead to the B terminal and I still have no output. All grounds are good and wiring is good. If my theory is correct, once the engine is started and the altenator is pulsed by the field wire from the charge light to start current flow, the internal regulator takes over for the charge line in adding current draw. Is the ignition switch not out of play at this point concerning the charge line? The parts house is not buying that it is another bad altenator - don't blame them. According to the Oldsmobile book there is a blocking diode in the field line down stream from the charge light. What is it's purpose?