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Charging problems

Tiny
GOODALEC
  • MEMBER
  • 1994 CHEVROLET ASTRO
  • 4.3L
  • V6
  • 2WD
  • AUTOMATIC
  • 125,000 MILES
We changed the alternator and battery checked all connections, but is still not charging the battery fully. Any suggestions?
Thanks
Thursday, February 2nd, 2017 AT 5:52 AM

9 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
What are the symptoms? Measure the battery voltage while the engine is running and tell me what you find.
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Thursday, February 2nd, 2017 AT 12:00 PM
Tiny
GOODALEC
  • MEMBER
  • 4 POSTS
Battery is new, alternator is new when started battery it at 11 then drops to ten not charging the battery I guess before we switched the battery and alternator I was driving and all amps to old battery dropped to zero on the dash monitor shut off radio and heater made it home.
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Friday, February 3rd, 2017 AT 11:59 AM
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
First, check for 12 volts on the large output terminal on the back of the generator when the engine is off. If that is missing, a very large fuse or fuse link wire is burned open. Next, look at the brown wire in the small plug on the side / back of the generator. Measure the voltage on that wire while the plug is connected and the ignition switch is on.
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Friday, February 3rd, 2017 AT 2:18 PM
Tiny
GOODALEC
  • MEMBER
  • 4 POSTS
Yes 12 volts on back of altenator 12 volts on brown wire with key on. Gauges 20 amp fuse was blown replaced and blew again. Will be checking connections at starter and fuseible link.
Thanks for the help.
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Friday, February 3rd, 2017 AT 3:11 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
Hold on. You have 12 volts on the brown wire with the plug connected. That has to come through the fuse you said is blown. Do you also have a pink / black wire in that plug?

Unplug that connector, then, with the ignition switch on, tell me what you find for voltage on the brown wire, the pink / black wire, and their two mating terminals in the plug on the back of the generator. Is the fuse still blown or removed? Does that fuse blow when the plug is disconnected at the generator?
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Friday, February 3rd, 2017 AT 3:26 PM
Tiny
GOODALEC
  • MEMBER
  • 4 POSTS
12 volts on brown wire 0 on the only other wire on clip. Fuse is removed it was blown first time checked. Replaced it started van and after testing battery while running (still only 12 volts)fuse was blown after shutting engine off
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Saturday, February 4th, 2017 AT 6:34 AM
Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
It sounds like the internal voltage regulator is shorted to 12 volts. Did you check for 12 volts on the terminal in the plug that corresponds to that brown wire? If there's 12 volts on that terminal with the connector unplugged, the regulator has to be shorted.

I have to think on this some more. Even the shorted regulator shouldn't cause that fuse to blow.
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Saturday, February 4th, 2017 AT 4:01 PM
Tiny
CHRIS ARMANINO
  • MEMBER
  • 1 POST
Did you guys ever get this fixed? My van is doing the exact same thing.
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Sunday, April 18th, 2021 AT 12:46 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Follow the voltage checks the tech left for testing and let us know the results.

Then we can further help. I attached a diagram to make is easier for you to test.

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Roy
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Sunday, April 18th, 2021 AT 1:20 PM

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