Battery/Charging problems
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Joined: Jul 1999
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From: Monroe, NC
Battery/Charging problems
Hey guys I have got one for you, my 86 in my signature is having some battery or alternator problems. The truck sits alot but this problem just started and it has been quite warm here lately so I know it is not a cold issue. I can jump it off after it sits for a week and after it runs for a while it will start after normal use. I just had the battery checked at Advance and they said it was just showing low charge, no surprise there. I checked the voltage with it running and with no accessories on it shows about 14.2 when I turn the A/C on it drops to about 13.2, I have checked the battery connections and they are tight. I am just wondering it the alternator is on its way out. Does this thing have a seperate voltage regulator? I know on my 88 mustang 5.0 it was built into the alternator. Thanks, Dan
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Joined: Feb 2004
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From: North Carolina
On my 86 with a 460, I believe that the alternator has an internal regulator. If you take it off, and take it to an advance or whoever, they can test it for you. Double check your cables for a bad ground/connection and/or corrosion. Before I bought my truck the previous owners went through 4 starters, and the only thing wrong was 17 year old ground cables.
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Joined: Jan 2002
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From: GANS
Actually, in '85, ford started using internally regulated alternators. some trucks got them, and some had the old standby-the externally regulated ones. By 86, they all should have the internally regulated ones.
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From: Monroe, NC
Well, the alternator checked good but since I had it off, and it was 19 years old, I decided to replace it anyway. So far so good. The new one does not drop but to 14.2 with the a/c and lights on and runs at 14.5 with them off. The test will be letting it sit and trying it next week. Thanks for the advice. Dan
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From: Monroe, NC
I should have know that would have been too easy. I checked the voltage on the battery on Sat. and it was down to 10.2, it started but barely. I turned it off and put a meter on it and started checking fuses. The only fuse that seemed to have any effect was the one for the interior lights, dash lights, according to the Haynes manual anyway. The lights are not staying on when the door is shut and I have not found any loose wires without tearing the whole dash apart, anyone have any ideas?? I checked all the ground wires I could find and all are tight.
Thanks, Dan
Thanks, Dan
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From: SE Texas
I'm having a similar problem on my 84 Bronco. I think it may be the battery discharging on it's own, probably has a bad cell inside it. When they get close to two years old, alot of them just won't hold a charge. Another truck I have was sitting for a few months, and it cranked right up this week. The Bronco will need a jump if I don't drive it for 3-4 days.
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Get the battery fully charged and then have it checked again and make sure they do a load test on it. Auto batteries can only deep cycle a couple of times before they are shot.
If the battery checks out then the next step is to find what is drawing on the battery when the motor isn’t running. To do this, remove the ground cable from the battery and put a voltmeter set on amps between the battery and the cable. Anything over about .5 amps is too much draw and means that something is draining the battery.
To find it you need to pull one fuse at a time and re-check the draw. When the circuit that is causing the problem is found the amps will drop. Then you know what to track down – something in that circuit. Things like glove box lights and such are frequently the culprits.
Good luck,
Mark
If the battery checks out then the next step is to find what is drawing on the battery when the motor isn’t running. To do this, remove the ground cable from the battery and put a voltmeter set on amps between the battery and the cable. Anything over about .5 amps is too much draw and means that something is draining the battery.
To find it you need to pull one fuse at a time and re-check the draw. When the circuit that is causing the problem is found the amps will drop. Then you know what to track down – something in that circuit. Things like glove box lights and such are frequently the culprits.
Good luck,
Mark
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Joined: Oct 2003
Posts: 418
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From: Nice, California
Yeah I think I might have a dead cell in my battery. When I put it on a battery charger it never gets fully charged (only like 90% and stops there). Sounds like it has a dead cell. It still shows around 14 volts. I was first thinking I didn't have a strong enough alternator, but I think it's the battery. It's almost 2 years old, so it might be time to replace the battery.
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