What next with charging system?

Tiny
KENT46725
  • 1994 FORD RANGER
  • 147,000 MILES

Still having the same problem with alternator not charging battery. Unplugged the instrument panel, thinking it was faulty because gauges are not working. Pulled one fuse at a time while using multimeter to check for short. I'm not getting any return charge voltage back to battery. Alternator has now been checked twice and tests good. Battery is new. I've traced wire that I was told by a ford tech that is the return feed from the alternator to the battery. Odd thing. It reads the same voltage as my battery, not the 13.2 to 13.8 that it should. I am running on the battery which isn't going to last much longer. Please help!

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Wednesday, May 9th, 2012 AT 11:20 AM

17 Replies

Tiny
WRENCHTECH
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Test the voltage at the main terminal of the alternator with the key OFF? What is the voltage?

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Wednesday, May 9th, 2012 AT 12:53 PM
Tiny
KENT46725
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Starting voltage was 12.4, after driving it for 2 days it has dropped to 11. I am getting the same voltage at the alternator main as I get at the battery.

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Wednesday, May 9th, 2012 AT 1:53 PM
Tiny
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That's not what I asked to to test.

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Wednesday, May 9th, 2012 AT 2:01 PM
Tiny
KENT46725
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Close to 12v like I already said. With key off.

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Wednesday, May 9th, 2012 AT 2:16 PM
Tiny
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Was this tested with the key OFF?

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Wednesday, May 9th, 2012 AT 2:36 PM
Tiny
KENT46725
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Yes, key off.

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Wednesday, May 9th, 2012 AT 2:45 PM
Tiny
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Test for power on the yellow/white wire all the time and the lt green/red when the key is on.

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Wednesday, May 9th, 2012 AT 2:49 PM
Tiny
KENT46725
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Ok I am at work, so will do afterwards. I think I had checked voltage on the y/w wire and have voltage there. But don't recall getting any at that point, but will test again and let you know. Thank you for responding so quickly.

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Wednesday, May 9th, 2012 AT 2:55 PM
Tiny
KENT46725
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Ok, pwr at y/ w constant. No power at g/ r wire when on. Next?

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Wednesday, May 9th, 2012 AT 8:24 PM
Tiny
WRENCHTECH
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OK, that wire runs from the ignition switch (gray/yellow) through the fuse panel and then to the charge light (gray/yellow) and from there to the alternator (lt green/red) and the circuit is broken somewhere. You are going to have to locate that wire and determine where it's losing it's power. I would be very suspicous of the fuse panel although it's just a splice. It doesn't pass through a fuse.

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Wednesday, May 9th, 2012 AT 11:55 PM
Tiny
KENT46725
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Ok, more questions. What is the green/red wire doing exactly? Does it signal the alternator to charge the battery? Is there a way that I could temporarily supply voltage to that wire to bypass the short for now. Would that allow the alternator to at least charge the battery? This is the only vehicle I have and until the weekend, I don't have time to find the problem area. If I could bypass it by cutting it somewhere and resupplying voltage from another source, where would be a good spot to connect it to? Thanks so much for your knowledge. I am definitely starting to see a glimmer of light at the end of the tunnel.

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Thursday, May 10th, 2012 AT 12:14 AM
Tiny
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First, I don't recommend rigging things like this because it can become dangerous and permanent but yes, it you supply KEYED ignition power to that wire, it should charge but the dashcharge light will not work.

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Thursday, May 10th, 2012 AT 12:21 AM
Tiny
KENT46725
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Alright, yeah, I don't like "rigging" things either. But if it will atleast charge my battery until the weekend that will be awesome! I'm thinking that I could cut the green/red wire under the hood at an easy access point for now and connect it to a point in the fuse box that is "keyed" power. So, if I am understanding correctly, I need to supply voltage through that wire to the alternator?

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Thursday, May 10th, 2012 AT 12:30 AM
Tiny
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That is correct, only when the key is on.

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Thursday, May 10th, 2012 AT 12:33 AM
Tiny
KENT46725
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Thank you very much! I can't tell you what a help you have been! I will proceed with the "rig" for now and take care of it the right way this weekend when I am off work. Hopefully it won't be too bad to find the "real" issue and get it resolved. You've been awesome!

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Thursday, May 10th, 2012 AT 12:40 AM
Tiny
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You're welcome.

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Thursday, May 10th, 2012 AT 12:41 AM
Tiny
KENT46725
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Just to let you know. It is now charging. And the weird thing is that the oil gauge is working but no others. Not sure about that, but all is good for now. Thanks again!

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Thursday, May 10th, 2012 AT 1:02 AM

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