Alternator drawing current with ign off

289 - 351 cid Small Block Performance
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GeneB
Posts: 68
Joined: Tue Sep 12, 2017 8:08 pm
Location: Commerce Twp Mi

Alternator drawing current with ign off

Post by GeneB »

Having a problem with the battery going dead in about a week with no driving. PO told me he had this problem & put a shutoff switch on battery. Checking today I disconnected all wires from + battery going to the starter relay. Connected amp meter between +bat wire and other wires one at a time with key off.
One wire drawing about 40 ma that goes to radio (Aftermarket). There are 2 other wires swaged to same terminal. Haven't found where they go yet.
One wire drawing about 120 ma. This wire goes directly to Alternator. It is the only wire I see on back of Alternator. Does that mean it has a built in regulator? This same wire was drawing 160 am when I first checked then going from 100 am to 120 am after I started car & then shut it off. It took about 1 minute to get to 120am

What is going on with alternator causing it to draw current with ign off?
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StPro
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Location: Coon Rapids MN
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Re: Alternator drawing current with ign off

Post by StPro »

Have the Alternator tested. Most likely a bad diode in the alternator. They act like a one way check valve to change ac to dc . If a diode goes bad it will drain the battery.
Only use the brakes to stop and get gas.
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GeneB
Posts: 68
Joined: Tue Sep 12, 2017 8:08 pm
Location: Commerce Twp Mi

Re: Alternator drawing current with ign off

Post by GeneB »

Going to take Alternator to the Auto Electric shop & have them check it out.

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