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Alternator won't charge

2K views 17 replies 8 participants last post by  Gagewebb 
#1 ·
Just replaced the alternator on my Chevy 350 and I can't get it to charge. It charged for a little bit right after first start up but then it's like it died again. Power to it is good. Ground is good. All other wiring is good. It was remanufactured and I have another one on the way. But maybe one of you guys can help me. I'm not too mechanically inclined.
 
#8 ·
When you say power is good to the alternator, which power are you talking about? There are 3 connectors on the alternator which are powered at least part of the time. Which wires have current and when (key on / key off)?
 
#9 ·
Ultima 01-0217
GM 10SI
Insure it is wired correctly.
You need to check to see if you have power to post 1 (A common issue is the alternator light burning out). If not then you found your issue
You can jump the battery to post 1 and see if it will start charging
 

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#10 ·
Power to battery and 2 are good. I traced 1 back and all wiring seemed fine. The previous alternator would still charge. But couldn't fully keep up. I changed nothing for this new alternator besides a new bracket and ground wire. And no charge whatsoever. So I'm led to the assumption I have a faulty alternator.
 
#11 ·
You said the battery is dead... Always charge a battery before running a new alternator as it can burn itself out trying to charge a dead battery. Delco Remy has that note in their instructions for their alternators.
 
#14 ·
Okay so I took it to the store and they tested it and it rates at 14.8 volts. So I came back home and rewired the entire thing and still will not charge. Battery is wired to the starter then from the starter to the battery post on the alternator. Then jumped over to the 2 terminal. 1 is then wired to the stater solenoid post that is only hot when cranking.
 
#17 ·
What is it, a brown/white wire from the bulkhead connector that goes to the alternator? The only "small" wires to the solenoid should be ignition module/coil resistor bypass power on the 'I' terminal and the start command wire on the 'S' terminal of the solenoid. Alternator wire goes directly from bulkhead connector by the brake master cylinder to the alternator, and the other wires goes from the alternator to the battery connection on the starter solenoid. The "smaller" possibly red wire form the 2 terminal plug can be connected to the alternator output post, same as the cable from the alternator to the battery cable side of the starter solenoid.
 
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