Battery wont charge

[MJ is dead]

Ok so here's the story

 

Last week I left my lights on at work, came out to a dead battery, duh. So we tried to jump it, no salt. Let it charge for awhile, then tried jumping it again, still no luck. Friend borrowed me a battery to get me home, but it was waaaaaay too big. I don't know the specs, I just know it was way bigger than the stock MJ one. That one lasted another oh...50 miles before it died, in the meantime I had the stocker on the charger at home, so after being limped home 50 miles, I decided to put the right battery back in my mj, that lasted until today.

 

Alright, so a battery won't hold a charge, must be the alternator right? Nope. The alternator bench tested fine.

 

I'm at a loss fellas. Brand new battery in january, and the alt. Is fine. What's next?

[Harper]

Any chance that there's another drain on it somewhere after you shut it down?

[MJ is dead]

That would make sense, if it had been dead a day or two after i put the fresh battery in. But I put the battery in last sunday, and its lasted this long. if I had a draw, I probabaly would have noticed by now

[Eagle]

if I had a draw, I probabaly would have noticed by now

That depends on how heavy the draw is. For example, the clock is a constant draw, but how many dead batteries have ever been caused by the clock?

[MJ is dead]

Cables were pretty nasty and corroded, so I'm gonna swap those out for starters, as well as the clamps.

 

Also, taking the nut off the stud on the ground-impossible. I had to cut all the wires going to it, and ended up spinning out the whole stud. I'll be replacing that with a bolt

 

And Eagle....I don't have a clock :rotfl2:

[1987Comanche]

What about the cable from the alternator to the starter solenoid (assuming Renix era)?

[HOrnbrod]

Have you started it, placed a voltmeter across the batt terminals, and read the voltage at 1500 RPM or so? Should be at least 13.5VDC.

[MJ is dead]

No don I hadn't. I knew that was one way to see if I had charging going on, but didn't have a multimeter till today (when its too late)

 

I pulled the little plastic cover off of where all the relays and crap are and noticed I had a shorted positive wire, what it goes to I don't know. Its possible we burnt it out when we were jumping it. It was like a freaking monsoon it was raining so hard that night. Hopefully that's it. If not, I have new cables, terminals, ans a new battery strap anyway.

 

Also pulled the bumper today and noticed a little green wire behind the vacuum blimp. Has a female spade connection on it, any idea what it goes to? :dunno:

[Eagle]

Also pulled the bumper today and noticed a little green wire behind the vacuum blimp. Has a female spade connection on it, any idea what it goes to? :dunno:

The right side horn. If your truck is a base model, it doesn't have dual horns.

[Unglar]

I pulled the little plastic cover off of where all the relays and crap are and noticed I had a shorted positive wire, what it goes to I don't know.

 

I had this same problem last week and found one of those wires was loose. My guess is after you fix the burned out wire your problem will be gone.

[MJ is dead]

I certainly hope so unglar :wall:

[MJ is dead]

Got it all back together, tested the voltage before starting it read 12.5 (fresh off the charger, so a little high, but no biggies) I started up the MJ and it read 14.2, so again a little high, but that definitely means its charging. Woohooo! Fresh cables and fixed a few connections, replaced the belt while I was at it.

 

Thanks guys! :thumbsup:

[HOrnbrod]

:thumbsup:

[Unglar]

:cheers:

[Harper]

Oh yeah, a shorted positive would definitely cause a power draw :yes: