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Honda Civic 2005 alternator problems

Since buying new my Civic VP automatic, it seems I’ve been plagued with electrical gremlins. Right off the bat, I noticed the lights would arbitrarily dim and brighten with no rhyme or reason. The dealer checked it and found no problems and could not replicate it. It still does it now at 117K miles with no predictable pattern. Also, it has always seemed to idle too low while crawling in Columbus, OH, traffic, with the battery light coming on when adding in temperature extremes (while running A/C or defroster) to the mix. At first, I was able to rev the engine in neutral or get out of traffic and open it up to make the battery light go out, but that doesn’t seem to help anymore. Also, I can make the battery light flicker just about anytime when I let off the gas. I had to replace the factory battery (under warranty) with one I bought off the AAA service truck. I had to replace that battery, too, along with the alternator (rebuild), at 88K miles at my local mechanic 2 years ago. It died again yesterday, on the interstate, after my vain attempt at getting up the rpm’s when the battery light came on strong. It’s at the AAA garage now where they said it needs another alternator (rebuild), but the battery is OK. I’m a little tired of paying $425.00 every 2 years for another alternator and my local mechanic said he never sees this happen on Hondas. I’m not sure if all of the above problems are related or not. Perhaps rebuilt vs. genuine Honda parts may be an issue, but that doesn’t explain the original alternator failure. Has anyone seen similar patterns with this era Civic? Did I miss an alternator recall? Any help or comments are appreciated.

It’s possible that the old battery contributed to the demise of the alternator. After the replacement alternator is installed have the current load checked on the alternator to make sure that is ok and something isn’t drawing unnecessary current draw on the charging system. Make sure the replacement comes with a warranty. Some alternators come with a lifetime warranty.

I couldn’t find any warranty information on the first alternator replacement, but I will make certain I get it this time. I’ll have them check the current load when I get the timing belt replaced in a couple weeks. Thanks a lot for the advice.

I’m guessing the rebuilt alternator was defective. Alternators have electronic parts inside them called “diodes”. For the alternator to work correctly, all the diodes have to be working. Here’s the thing: An alternator will still work – marginally though – even if one or more of the diodes fail. The symptom what you are reporting is exactly what you expect in the event of partial diode failure in the alternator.

My first guess would be to simply replace the alternator – again. If it were me, I wouldn’t use the same source as you used before. If you don’t have time to mess with this problem any more, drive over and get a new alternator from the dealer.

Alternators can fail due to a bad battery, but the primary cause is that the positive terminal gets shorted out to ground while the car is running, or even if the car isn’t running, this can damage the alternator. This is why auto mechanics disconnect the battery ground strap when they work on a car, especially if they are working on the electrical system. It’s to avoid damaging the alternator diodes.

Thanks George. I have the car at a different shop this time for the second alternator, but its another rebuilt, so I hope for a better result this time. If this happens again, I will definitely get a new one - or a new Hyundai.