With all the wires disconnected from the positive post of the battery, Should I get a voltage reading of 12.5v on the wire to the alternator, by putting one lead of volt meter to the + post on battery and the other lead to the wire leading to the alternator.
I am having a battery drain problem.

2000 chevy 3500 standard cab,. 5.7 engine.

 

Yes, of course. You're completing the circuit.<O</O
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With the battery disconnected at the negative post, remove the large battery connect wire at the alternator. With you meter on "ohms", test for leakage between that big alternator post and ground. Then reverse the leads and do it again.<O</O
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One direction you should get continuity and the other "zero". If you are seeing a reading in both directions, you have a leaking diode within that alternator.<O</O
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Allan<O</O
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Would a leaking diode drain the battery overnight.

 

Yes Sir, it's a straight shot to ground.

First order of business tho should really be a through test of the battery to make sure we're not dealin' with some problem there.

Allan

 

OK, Thanks Allen.
The battery is questionable. Will have it checked before I go any further.

 

Diode checked ok. I just went and bought a new battery a few days ago, and it is still holding up well. I am assuming it was a battery problem.
thanks for your help and input. Appreciated very much.

Thanks, Earl