Battery not charging
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Freshman User
Joined: Sep 2004
Posts: 28
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From: Vancouver Island
Battery not charging
A problem recently surfaced in my '81 f-150. My battery isn't charging when the truck is running. My battery is less than a year old and I just changed the alt. I checked over the wiring compared to my Haynes manual and the only thing that didn't seem to match was the feed from my voltage regulator marked 'I' aparently is supposed to run to bat+ at the starter relay. Mine however, runs through my firewall with a mass of other wires. These then go up into my dash. Can anyone account for this discrepancy? Should I try connecting 'I' to my bat+? This problem just popped up on it's own and I'm about to take it in for a diagnostic.
Elder User
Joined: Apr 2004
Posts: 535
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From: Tucson, AZ
Since the problem just recently started happening it's probably not the wiring routing, could be a new open or short but doubt it's the wiring routing. You might want to test the voltage regulator, I had mine go bad which caused a charging problem. Voltage regulators are commonly overlooked.
Postmaster
Joined: Feb 2003
Posts: 3,441
Likes: 5
From: Muskegon, MI (home)
Originally Posted by srercrcr
Clean all connections that battery cables touch.
2006 - 1981 = 25 years.
Plus, remember Rule One....it's usually the simplest things.
2006 - 1981 = 25 years.
Plus, remember Rule One....it's usually the simplest things.
Tuned
Joined: Jan 2006
Posts: 290
Likes: 1
Chased my tail on battries charging twice. A Corvair got a complete new motor wiring harness before I was done. The problem was in the "new" rebuilt alt. Someone forgot to place a nut inside the alt on one of the wiring post. The alt worked ok at low speed and on test bed. Grounded/arked out when it got hot. Tuff to find that problem.
The other 64 Ford van problem was a old battery. I installed new batt cables and I forget what else. It's been 26 years ago. Any way it was the junk in the bottom of the old batt. It would sometimes short out the other plates. Replaced the batt and things were great.
The other 64 Ford van problem was a old battery. I installed new batt cables and I forget what else. It's been 26 years ago. Any way it was the junk in the bottom of the old batt. It would sometimes short out the other plates. Replaced the batt and things were great.
Senior User
Joined: Jul 2003
Posts: 311
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From: Nashville
As others have said, double check your battery terminal connections, the chassis ground, and the alternator output wire. Even if the battery is only a year old you should check the water level in the cells. Do that and still nothing... have your alternator bench tested [most auto parts stores will do it for free] and replace the voltage regulator [they're cheap, about $12].
If your alternator is "dead" it's probably just worn out brushes. You can replace them yourself for about $4 in parts.
If your alternator is "dead" it's probably just worn out brushes. You can replace them yourself for about $4 in parts.
Posting Legend
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Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
I would not believe anything in a Haynes Manual.
The "I" wire never goes to the Battery.
Since you said the "I" wires goes to the firewall that means you have an Indicator Light.
Here is a diagram that would be close.
The "I" wire never goes to the Battery.
Since you said the "I" wires goes to the firewall that means you have an Indicator Light.
Here is a diagram that would be close.
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Fleet Owner
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From: Easton,Ks
Now for the problem.
You should have the following:
Unplug the Voltage Regulator.
The "I" wire should have power on it with the key on and no power with key off.
The "A" wire should have power at all times.
The "BAT" wire at the alternator should have power at the Alternator at all times.
With your test light check the above and one of the items will be wrong, let us know what you find and we will help you from there.
If you do not have a test light get one.
You should have the following:
Unplug the Voltage Regulator.
The "I" wire should have power on it with the key on and no power with key off.
The "A" wire should have power at all times.
The "BAT" wire at the alternator should have power at the Alternator at all times.
With your test light check the above and one of the items will be wrong, let us know what you find and we will help you from there.
If you do not have a test light get one.
Last edited by subford; Apr 11, 2006 at 07:56 AM.
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