Rep Power: 0

Okay guys, I have been having an issue with the battery light . I have a 02 Civic Lx 1.7 SOHC ... I was cruising at 40mph when randomly the battery light came up . As soon as i got back home the first thing i did was remove the alternator and took it to the neighborhood autozone were they tested it and i came up to be fine..... with that i reinstalled it , when i turned the car on everything was back to normal the batt light went off . the next day i took it for a drive and the light came up on again. But what i noticed is that once i pass 3k it turns off and when the rpm drop below 2k it comes back on....??? today i brought out the multimeter and with the car off i checked the batt voltage (12.5v). i turned on the car and the bat voltage remained 12.5v. i connected it to the alt. output and i got 12.5v. Even when i reved past 3k the output was still 12.5v. I connected the probes to the field connector and i am getting the respected readings ( 12.4v,4.8v,5v,0v) Does anyone have any ideas whats going on??? Thanks In advanced!!!! I appreciate all help!!!!!

Matt

 
Rep Power: 0

My battery light came on and turned off for a few days until it eventually stayed on. About 60 miles later, my car died and it turned out to be the
failed alternator.

 
Rep Power: 811

classic bad alternator. most of the guys at auto stores do not know how to test an alternator. and if youre a noob, 20 amps is considered "good" when it should be 70 amps. everything you describe points to an alt not producing enough power, esp that the light goes off when the rpms are higher, since it is prolly barely making enough power to keep the battery light off. and your own output readings when revving should be around 14v, not battery voltage of 12.5v

 
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hey gearbox thanks alot for the reply, ill get back with the final resolution.

 
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I had a very similar thing happen. As other have said, it's more than likely the alternator.

 
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It ended up being the alternator... Got a new duralast for $130 with a lifetime warranty. LESSON LEARNED FROM THIS THREAD: Do not always trust your local autozone alternator test.

 
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lol, when I lock my doors: I see the headlights loosing a little bit of the power. That only happens when I press "Lock Doors", after that it comes back to normal. Same happens with the interior lights, but I'm not worried, I still think it may be my battery.. the car runs like that more than 1 year
But yeah, I don't have the 7th generation, so my post is kinda useless...