Alternator not charging?

Tiny
DODGE71
  • MEMBER
  • 1997 FORD RANGER
I HAVE 1997 ford ranger and it quit charging and I replaced the battery and the alternator and it still is only showing 11.5 volts/ What is the problem. I have replaced the alternator and the battery and still is only putting out 11.5 volts
Wednesday, January 11th, 2012 AT 11:29 PM

16 Replies

Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Do you have a alternator to do some testing? this guide should help

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

Please run down this guide and report back.
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Wednesday, November 29th, 2017 AT 2:21 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
All connections/cleaned okay-could be the computer controlled of the alternator field generation circuit-have it checked out
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Wednesday, November 29th, 2017 AT 2:21 PM
Tiny
DODGE71
  • MEMBER
  • 8 POSTS
Should I have juice on the green wire going to the alternator. My neighbor was driving down the road and it just stopped charging.
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Wednesday, November 29th, 2017 AT 2:21 PM
Tiny
RASMATAZ
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  • 75,992 POSTS
You should have power on the light green and red wire-check fuse no.15
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Wednesday, November 29th, 2017 AT 2:21 PM
Tiny
DODGE71
  • MEMBER
  • 8 POSTS
Checked thefuse, replaced the alternator with 2 new ones, I had read that I was suppose to have juice on the yellow wire and the green wire and the green wire is dead all the way back to the firewall. I have check any farther yet.
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Wednesday, November 29th, 2017 AT 2:21 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Black with a orange stripe should have power and the Yellow with a white stripe shoulod have power.
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Wednesday, November 29th, 2017 AT 2:21 PM
Tiny
DODGE71
  • MEMBER
  • 8 POSTS
I have been trying to find a wiring diagram for this, because the only wires that have juice is the red wire that hooks to the back and the yellow wire on the plug in. I have checked the fuses and the fuses are good, but I have found a couple of fuses that have no power to them and it does not make any since, because one of them is the left front light and it is working.
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Wednesday, November 29th, 2017 AT 2:21 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
I posted a wire diagram of the alternator wire colors does it look like your wires?
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Wednesday, November 29th, 2017 AT 2:21 PM
Tiny
TOWNSENDWL
  • MEMBER
  • 1 POST
  • 1997 FORD RANGER
  • 95 MILES
Replaced Alternator after it tested bad. Replaced with a rebuilt one and still the battery does not charge, it reads 11.67 VDC What else could it be

Checked all connections and cleaned battery posts
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Thursday, December 10th, 2020 AT 8:40 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Check fuseable link between alt and battery. If bad, a good alt will still not charge.
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-1
Thursday, December 10th, 2020 AT 8:40 AM (Merged)
Tiny
JDAFIXA
  • MEMBER
  • 1 POST
  • 1995 FORD RANGER
  • 2.3L
  • 4 CYL
  • 2WD
  • MANUAL
  • 178,000 MILES
On another of your threads, you explained how to check voltages at the harness at the alternator. Full voltage on yellow/white, 2 to 3 volts on green/red with key on. Are these tests done with the harness unplugged from the alternator, or do I need to poke little holes in them with it plugged in? Also, if full voltage on the green/red (which is what I am getting) "check that harness for bad connection". Meaning a bad connection where? Internally, at the alternator terminals or somewhere else? Could you please elaborate?
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Thursday, December 10th, 2020 AT 8:40 AM (Merged)
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
Disconnect the connector at the alternator and check voltage at the black/orange wire to verify the fusible link is good (12 volts), 12 volts on yellow/white. The light green with red is responsible for turning on charge indicator in the event of alternator failure. Honestly I never have to deal with that wire. Start with the two power circuits to be sure you have power to the alternator. And never poke through wire insulation as it will be a starting point for corrosion. A thin paper clip or a back probe kit is best because they slide in the back of the connector without doing damage. Great question though! Good luck!
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Thursday, December 10th, 2020 AT 8:40 AM (Merged)
Tiny
CARHARTT3009
  • MEMBER
  • 3 POSTS
  • 1995 FORD RANGER
Electrical problem
1995 Ford Ranger 6 cyl Two Wheel Drive 270000 miles

I purchased the 95 ranger about six months ago. I just replaced the alternator, and it appears to be hooked up correctly, but now the battery is dead and will not take a charge. My question is, will a new alternator end the life of an old battery that is used to getting a weak charge off of an old alternator?
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Thursday, December 10th, 2020 AT 8:40 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Battery could be sulfated-get it load tested to check its condition. Or could be a short circuit eating up the battery overnite
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Thursday, December 10th, 2020 AT 8:40 AM (Merged)
Tiny
CARHARTT3009
  • MEMBER
  • 3 POSTS
So a sulfated battery is bad is basically what I am getting from online research. It was a matter of hours that the battery went dead. And now it won't take a charge, I let it run for over an hour, and shut it off then on, and nothing. I was just assuming that the new alternator killed the old battery with a strong charge going to it.
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Thursday, December 10th, 2020 AT 8:40 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
If the new alternator overcharging the battery it will ruin it and can explode
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Thursday, December 10th, 2020 AT 8:41 AM (Merged)

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