Another electrical thread

cmagee

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Oct 21, 2010
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Before the powers that be crucify me, yes I'm aware of where the search button is and I've read every thread that pertains to my issue, but if there's one I missed, I apologize in advance.

Driving my truck the other day in the desert, check gauges light comes on and voltage is on 8, or 0, whichever means pegged on the low end. Truck is still running fine so I get home as fast as possible to investigate. Check terminal clamps and they're a little loose so I tighten them. Problem solved right?
Getting colder out here so I was used to voltage not coming up to 14 until after the truck had warmed up, but instead, kept dropping off, as well as throwing a check engine light, all voltage related. Get to work to my tools, turned truck off waiting on a bay to look at it, go to start again and nothing. Get a jump and as soon as the cables are off, truck is running incredibly rough and then dies. Ok, alternator is out. Replace that yesterday. Same issue. Get to work today for more investigating (note: neither battery has gotten hot or boiled over the typical behavior from this). Pull every ground and clean/replace, clean battery terminals, run jumper cable from pos to pos and neg to neg, nothing is bringing the voltage up. Then I notice my alternator is too hot to touch after under a minute of run time. I'm guessing that's what killed the last one. The only part I haven't replaced in the system are the wire that runs from the back of the alt to the passenger battery, the plug in the side that runs to the main harness, and the ecm. I'm hoping it's not the latter of the three. Anyone have any ideas? Or something I missed in another thread?
 
Have you measure the voltage coming out of the alternator durning this and what's the voltage at each battery?
 
Driver Batt:13.58V
Pass Batt: 13.68V
Alternator Stud: 13.72V
Alternator Plug: 12.92V
 
How old are your batteries? Have you tested them? Any acid leaking from them? Could be a battery with a bad cell. Most the times it's the pass side one from what I've seen.
 
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