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Discussion Starter #1
I have a Bronc that is eating batteries overnight and have tried all of the tricks to find a short and nothing so far. So I am diconnecting my positive termin al each night.

I had the alternator bench tested and it tested just fine at idle and at high RPM. So I am stumped.

Today I was riding over some rough road when my voltage started going nuts. I pulled over and saw what I suspected, my postive cable popped off (I had not tightened it down good enough).

Here is the question, shouldn't the voltage have stayed pretty normal even with the batt disconnected one the truck is running? Does this point to a regulator (internal to the alt) problem?
 

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ate lug
88 + 96 broncos, 96 F250
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If everything is in proper working condition, you should be able to take one lead off the battery and not effect the voltage. But, issues with the alt, or the regulator, charge cable, alt ground, engine ground, battery ground, fusible links, the starter relay or other stuff could cause this problem. Id say to get the alt tested to see if its working properly, but since you already did that, its gotta be a wiring issue, so start checking everything.
Also, are you sure you dont have any circuits that are staying on overnight?
 

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Discussion Starter #3
I have tested for open circuits using the method of pulling fuses and found nothing. I am next planning on checkingthe wiring at the fusable links in the engine compartment.
 

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Rest in Peace Friend...
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pjmorgan22 said:
I have a Bronc that is eating batteries overnight and have tried all of the tricks to find a short and nothing so far. So I am diconnecting my positive termin al each night.

I had the alternator bench tested and it tested just fine at idle and at high RPM. So I am stumped.

Today I was riding over some rough road when my voltage started going nuts. I pulled over and saw what I suspected, my postive cable popped off (I had not tightened it down good enough).

Here is the question, shouldn't the voltage have stayed pretty normal even with the batt disconnected one the truck is running? Does this point to a regulator (internal to the alt) problem?
I would venture a guess that the fluxuation in the voltage was caused by the loose battery cable and that if you went out, started the engine and took it completely off you would not see a fluxuation and the engine would run just fine.

As far as the discharging problem, remove the negative lead. Rig up a 12V bulb with leads and insert it inbetween the negative post and the negative lead. If it is lit you have a short that is draining the battery. Pull the fusable link leads off the start solinoid one at a time or remove one fuse at a time to see which circuit is causing the draw. Once you find that further break it down. Check for locations that the failing cable runs close to a metal surface for a rub thru short, these often don't blow the fuse because they are often high resistance shorts.


Good luck,

:thumbup
 

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Discussion Starter #5
Seabronc said:
I would venture a guess that the fluxuation in the voltage was caused by the loose battery cable and that if you went out, started the engine and took it completely off you would not see a fluxuation and the engine would run just fine.
The cable was completely off...it fell in front of the battery
 
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