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Alternator short circuit

I have a 1993 Volvo 240 wagon. I just replaced the alternator, but when it came to connecting the wires I ran into problems. Every time I attach the battery cables I hear sparks and the alternator goes 'pop'. I'm guessing that there's a short circuit, but I'm not sure how to fix it. I connected the wires to the terminals as follows (Thick red to B+, Thin red to D+, Thick green to other terminal)

I disconnected the green wire and clipped the negative end of my voltmeter to it. Then I touched the positive end to the alternator. The entire alternator was electrified, even though the car was turned off. Is this normal?

Is there something else I'm supposed to know about connecting these wires?

Any help would be appreciated.

Thanks,

-r

Reply to
richardson.randall
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Thick green is probably blue, and is the ground connection since the alternator is mounted in rubber bushings. connect this wire to one of the long screws that hold the front and back halves of the alternator together. The alternator is connected directly to the battery (through the starter motor terminal), it doesn't drain the battery due to the diodes.

Reply to
Mike F

Mike, Thanks for your reply. As far as the entire alternator being charged when the key is in the off position, is this a normal thing? I'm wondering if maybe the alternator I put in is the problem?

Mike F wrote:

Reply to
richardson.randall

Yes, the alternator is connected to the starter motor, to the same terminal as the big red wire from the battery. So the alternator is live all the time. Who knows if you've fried something by connecting the ground wire to the wrong place.

Reply to
Mike F

It turns out that the ground wire wasn't firmly attached to the chassis. I located the other end (hidden under the oil filter) and I saw that it was loose. Once I tightened it there was no longer a charge on the alternator case, and the only place that had a 12 V charge when the car was off was the battery terminal. Everything works fine now.

Thanks for your help.

-Randall

Mike F wrote:

Reply to
richardson.randall

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