# HELP! Reversed terminals on the battery...



## hans747 (Jul 14, 2005)

This wasn't me, but it just happened to a friend who I work with. His battery died the other night, and he tried swapping in a another battery from one of his other cars. Turns out the terminals were reversed on this battery, and it was dark out. You can imagine the rest... 

That battery was only attached for a matter of a few seconds, but now his car is host to one big electical gremlin. No lights are coming on, his stereo is blanked out, and he still does not know if the car runs (until he gets a battery strong enough to turn the starter). He checked all fuses, and they look good.

Has anyone done this before? Where is a good place to start looking for the answer to his problems?

Thanks!


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## zellx2004 (Sep 30, 2004)

Are you trying to say that the battery has reversed it's polarity? If So, this is the second time I've ever heard this happen. (I'm the first :thumbup: ) But, I haven't gotten another battery yet. I'll send you a PM, and talk to you about it.


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## rogoman (Dec 16, 2004)

hans747 said:


> This wasn't me, but it just happened to a friend who I work with. His battery died the other night, and he tried swapping in a another battery from one of his other cars. Turns out the terminals were reversed on this battery, and it was dark out. You can imagine the rest...
> 
> That battery was only attached for a matter of a few seconds, but now his car is host to one big electical gremlin. No lights are coming on, his stereo is blanked out, and he still does not know if the car runs (until he gets a battery strong enough to turn the starter). He checked all fuses, and they look good.
> 
> ...


There's a good chance that the ECU and the alternator went to heaven. Always remember that on most cars, NEGATIVE (-) BLACK, goes to ground and POSITIVE (+) RED is the hot side. On some batteries, the + and - posts are reversed; ALWAYS check the polarity.


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## Joel (Jun 11, 2003)

At minimum hes blown a number of fuses and or fusable links


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## zellx2004 (Sep 30, 2004)

rogoman said:


> There's a good chance that the ECU and the alternator went to heaven. Always remember that on most cars, NEGATIVE (-) BLACK, goes to ground and POSITIVE (+) RED is the hot side. On some batteries, the + and - posts are reversed; ALWAYS check the polarity.



Please don't say that the ECU went to heaven. My battery did the same. I hope my ECU isn't fried.


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## The$nail (Jul 29, 2005)

hans747 said:


> This wasn't me, but it just happened to a friend who I work with. His battery died the other night, and he tried swapping in a another battery from one of his other cars. Turns out the terminals were reversed on this battery, and it was dark out. You can imagine the rest...
> 
> That battery was only attached for a matter of a few seconds, but now his car is host to one big electical gremlin. No lights are coming on, his stereo is blanked out, and he still does not know if the car runs (until he gets a battery strong enough to turn the starter). He checked all fuses, and they look good.
> 
> ...



Two things.

1= replace the grey alt 75a fuse that is located in the enginebay fuse box. That will make your lights/radio and stuff work again.

2= when you do that, if on your gauge cluster your dummy lights turn on , then you crapped out the alternator. That means you can go only as far as the battery has juice, since there is no recharging.

My guess is both are F***ed, but it never hurts to make sure the alt fuse only crapped out before buying an alternator.


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## hans747 (Jul 14, 2005)

The$nail said:


> Two things.
> 
> 1= replace the grey alt 75a fuse that is located in the enginebay fuse box. That will make your lights/radio and stuff work again.
> 
> ...


Thanks, I'll pass that along to him. It's a good place to start. Is it just a generic 75-amp fuse? or is a proprietary nissan part?

as far as ECU's go, that shouldn't cost too much to replace (if need be). Those things are a dime a dozen from junk yards. My buddy just bought one for his 92 Accord for about $15.

Eric


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## hans747 (Jul 14, 2005)

rogoman said:


> There's a good chance that the ECU and the alternator went to heaven. Always remember that on most cars, NEGATIVE (-) BLACK, goes to ground and POSITIVE (+) RED is the hot side. On some batteries, the + and - posts are reversed; ALWAYS check the polarity.


Thanks for the fatherly advice. That lesson have been learned in a big hard way.


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## hans747 (Jul 14, 2005)

The$nail said:


> Two things.
> 
> 1= replace the grey alt 75a fuse that is located in the enginebay fuse box. That will make your lights/radio and stuff work again.


It turns out that this was all that went wrong. The car is back on the road and very happy again. Thanks!


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## The$nail (Jul 29, 2005)

hans747 said:


> It turns out that this was all that went wrong. The car is back on the road and very happy again. Thanks!


Yes… Im a genius of mass proportion


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## Matt93SE (Sep 17, 2003)

don't get too full of yourself.
I've seen this happen dozens of times in Nissans due to the posts being reversed on them compared to domestics. done it myself once...
nonetheless, the worst its ever done is fry a couple of fusible links and pop the main fuse. replace those and I've never had a car with problems after that.

not to say it won't or can't happen, but that's the worst I've seen happen in the 15 years I've been wrenching on cars.


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## Seikenman (May 11, 2004)

Did it to my 240...blew a crap load of fuses...ECU seems to be fine tho


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