GM 1 Wire Alternator

This is simple - you wired it wrong. 1 wire alternators do not support idiot lights.

Have you given thought to the possibility that the alternator is bad??

Too, I had a internal alternator that would discharge like you said, due to the 1 and 2 wires being transposed. Charged fine, but would discharge the battery overnight.

Oh, yeah, you NEED the light AND resistance for it to work properly. Do you have both??

Cosmo

 

Probably backfeed. If you disconnect the alternator when the run on is occurring and the engine shuts off, put a diode in line with the exciter wire on the alternator


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Cosmo what would be the proper way to wire it. This is my first time doing this conversion.


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This is why you connect the resistance wire to the accessory terminal. If it's connected to the ignition terminal, the alternator feeds power to the ignition system after you turn the switch off. If you use the accessory terminal, when the switch is turned off, the alternator isn't connected to the ignition.

 

^^^ Well that was easy, and it worked! I'm still confused though, if the idiot light goes to the ignition terminal why doesn't it back feed through that and keep the engine running? And why the need for the resistance wire (I'm using a standard wire) going to the acc terminal in the diagram above? Is it to create resistance so current will run down the other wire and light the light?

Thanks all for the help.

 

You need to start another thread. And include SOME information. More than "one wire alternator - generator light still on".

Cosmo

 

Like someone said, the resistance wire is in parallel with the idiot light when the engine is running or the ignition is on. The resistance wire is probably in the 15-20 ohm range.

The diagram is right out of a GM manual, and yes, it does run the battery down in ACC mode with radio playing.

 

Thanks for the resistance spec. Seems to work fine with standard wire, if the only reason for resistance has something to do with the idiot light then I'm good.