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amr530711

Where does this wire go? Big black one on the battery

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car died today, dash went blank. I'd done most of my morning errands, starting and stopping several times. The last time, however, I started the car, backed out of the parking spot, and just started moving forward when it bucked, the dash went blank, came back on, then went blank again. No power anywhere. Radio doesn't work, no four way flashers, no power to windows, no bells, clicks, nor any other noises. Red cable from positive post of battery goes to the Sam, if it is powered separately, all the lights, locks, windows, and the radio work (radio needs the codes reset), but not the starter.

The black cable appears to have a solid short, but I can't locate the end of it (car is still sitting in a parking lot). Does anyone know what it connects to? Is it the starter, the alternator, or something else? I'll be going back tomorrow with more tools and a fully charged battery, the one in the car was quite warm and reading less than 4 volts, even though it was enough to start the car initially.

Not sure if it's a co-incidence or not, but the bucking happened at roughly the same time as the alternator usually activates.

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My guess you have one hell of a short going on. Was it the positive or negative lead on the battery?

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I've seen something like this...the power wire to Starter/Alternator, chaffes on the back of the starter and shorts to ground through starter case. You'll have to remove the Alternator to access it, I'd recommend not connecting a battery until it's fixed.

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Yes, massive short to ground, AKA poorly controlled arc-welding. The direct cable to bring the high current to the starter has rubbed through its insulation and is touching metal. Probably where Bessy described and caused by poor service practices, it was yanked too hard quite some time ago and popped out of position, years later it wore through.

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a progress report.

Got the car home, put it on jack stands and pulled the alternator. With the cable disconnected from the alternator, the short is gone. Looks like the problem is not in the cable between the battery and the alternator. I can't find any chaffing on the cable between the alternator and the starter, either. Hooked the two cables back together (minus the alternator) and don't have a short - in fact, I was able to start the car, and all of the electrics seem to work. I'm taking the alternator in tomorrow to get it properly tested.

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Had a similar problem years ago in my Toyota Van. Just pulled off at the lights and it died....No electrics.

After pushing to the side of the road, checked everything, cables warm - battery warm. Same story about 4volts from battery. Could not jump start with second battery attached.

End result found battery had inploded, after pulling off the cell caps, totally destroyed inside the battery. New battery and everything worked as normal.

I was told by autoelectrician that it happens very rarely for no reason.

My 2 cents worth :icon_smile:

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