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I just installed a GM 78Amp 12si Alternator and I took out the gen light/resistor and connected the White and Blue/black associated with them together. I supplied both terminal #1 & #2 on the alternator with the voltage from the black/blue wire. The car started fine and voltage measurement indicated that the battery is being charged. HOWEVER! When I turn the key to the off position and even take it out, the motor continued to run. I took the power to the radiator fans off too, but that make no difference. I found out that if I separated the connection at the gen light, the car will then turn off. For some reason, there is voltage there even with the key in the off position. That is not the case when the engine is not running. Any insight on this will be greatly appreciated...
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The #1 terminal is the "excite", which is normally supplied from a switched 12v source, usually from the charge indicator light.

The #2 terminal is the "sense", which is normally supplied from an always hot source.
Connecting these two terminals together and connecting them to the blue/black wire AND by-passing the charge indicator lamp will cause voltage to back feed through the blue/black wire and to the ignition system.

Putting the charge indicator light back into the circuit will cause the #2 "sense" terminal to receive a lower than normal voltage signal, and will cause higher than normal charging system voltages. The #2 wire needs to be connected to a 12v source, preferably unswitched.

John
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