Flickering headlights but good alternator
 

I've searched not only this forum but others and can't seem to find what's going on with my 2005 civic ex 2dr. Hopefully someone can help...

It has only 78K on it and an alpine system with kicker amp (350W). All works fine when the car is running on battery or when the car is running but on idle. When the rpm goes up, lights start flickering and my kicker amp shuts down. :hithead:
But the thing is its not all the time... Just most of the time.

I had the alternator tested twice by autozone and another mechanic and they all say battery is good and alternator is good. So what the hell is this problem?

Whe the rpm goes up the lights start flickering faster and faster and slower and slower as rpm come down. But at idle, all is fine!!!

I checked the connections to the battery and alternator all seem pretty tight..

Any ideas what I can do next?

Thanks

Re: Flickering headlights but good alternator
 

Hmmm flickering speed is dependent on rpm. Sounds like it would have to something that's attached to the engine that varies with engine rpm. I can only think of one major electrical regulating component that would cause that kind of symptom.

Alternator. :)

I had the same issue with headlight flickering in my 2002 ex 4dr. It seemed like the rectifier assy inside the alternator wasn't working correctly. And it wouldn't flicker consistently either. I didn't even both having it tested. I replaced it with a Honda reman and it fixed my problem.

I know you had it tested 3 times, but I don't know what else it could be based on just the rpm dependent symptom alone.

I'm sure somebody else will chime in with an answer since I'm sure you're convinced the alternator is good because of all the testing you had done on it.

Good luck with it. If you find it wasn't the alternator, let us know what it was. :)

Re: Flickering headlights but good alternator
 

This strikes me as odd. What voltage does it take for the amp to shut down? I know my old amp would keep going until the battery was too dead to start the truck.

Again: What voltage does it take for the amp to shut down? High voltage or low voltage shutdown?

Do the lights get DIMMER or get BRIGHTER as they flicker?



Is this an original alt?
Timing belt done recently, or any other work that would involve touching the alternator?

Make sure the alternator bolts are tight.



If you had someone test the alt and it was not acting up at that very time, then it surely will pass. It needed to be tested WHILE it was acting bad.



For some reason, I think I might want to hold the RPM to where the lights are flickering, then smack the alt with a hammer to see if there is any change.

Re: Flickering headlights but good alternator
 

assuming all your wiring is good and connections are all tight,

assuming your alternator belt is tight,

assuming your alternator bolts are all tight,

i would say you need a new alternator, and possibly a battery also,

although i think your going to keep frying alternators fairly quickly with an amp like that,

good luck

Re: Flickering headlights but good alternator
 

I just posted this in another thread.

This describes normal operation. First item on the first page:
http://dvpatel.homelinux.com/forumfiles/SN/A001200.pdf

Re: Flickering headlights but good alternator
 

According to the kicker doc the voltage must be between 10-16 volt. But I don't have a way to read the voltage when it's bad. Been to sears & pep boys and they don't have a tester I can test the alternator and record some numbers... Probably I gotta go back to my mechanic...

The lights get brighter when they flicker...

No timing belt changes as it only has 78K on it and no jobs to it other than the usual oil & brake changes...

Alternator is the original. The belts all seem tight enough. The bolts (only visible from top) seem tight enough but I can verify it with a wrench though... If there are bolts in the underneath, I'd have to check for that too...

There's a 60amp fuse that feeds to the kicker amp. I removed the fuse to kill the power to the amp to see if flickering would stop & it didn't. Amp no amp flickering is still there...

Thanks to the PDF, I have to check the relay box for the ELD to see if I can increase the currant throughout the car. But will this not burn the computer or other devices?

Re: Flickering headlights but good alternator
 

Uh oh.
Alternator.
Voltage sounds like it would be going from normal 14.6 up to over 16 volts, and that isn't good. Does the airbag light come on at that time too? (It may take more time to turn that on though. Flickers may be too short.)

Sure they do.
Buy a DVOM.
Connect it.
Look at it when the car acts up. (If it can react fast enough to show the voltage change.)



The alt bolts normally don't become a problem until after someone touches them.

Human error, and it is damn common. I did one timing belt just this week on a 7th gen and left the big one loose, but I DID catch it and correct it before I ran the engine. And I have done a few hundred of these, so there. Sh!t happens.


If you don't have the ELD code, I wouldn't concern myself.
If you DO have the ELD code, just replace it as per the bulletin about it.
If you have the amp wired directly to the battery + cable end, you may want to move it to tap in the fusebox so current for the amp goes through the ELD instead of bypassing it.
You can search for ELD bypass too, that would keep the charging rate from dropping under low load conditions, but I'm sure there is some trade offs.

Re: Flickering headlights but good alternator
 

Shame on you. I didn't think you made mistakes. ;)

Re: Flickering headlights but good alternator
 

Some days I am more human than others.
That was one of those days, I guess.
Hell, some days I feel like I couldn't fix a sammich.


I will never be in management, I can man up and admit I make mistakes.



Although, in reality, it is only considered a mistake if it gets returned to the customer that way.

I caught it before it got out the door. Fair game. :tup:

Re: Flickering headlights but good alternator
 

if you think that is bad, imagine the assembly line guys and the stuff they forget when the car is being put together.

Re: Flickering headlights but good alternator
 

I've worked with a few other car lines in the past.
In general, Honda seems to be really good about getting complete cars out the door consistently.
It isn't like we have to finish building the cars when they come off of the truck (FIAT).

Re: Flickering headlights but good alternator
 

Well after several tests and thanks to all of u I've decided to change the alternator. So it's likely that the alternator produces the right voltage but the diodes can't handle the load or the distribution of electricity to the cars components. Basically I gotta start with the alternator.

My mechanic says Bosch is preferred. Any other brand better or Bosch should do?

Thanks,

Re: Flickering headlights but good alternator
 

I think Honda Reman OEM(MITSUBISHI) is better and more reliable than any aftermarket. JMHO.

Link below and probably cheapest with shipping from here:

http://www.hondaautomotiveparts.com/...8MITSUBISHI%29

Re: Flickering headlights but good alternator
 

my oem lasted 2 yrs. im going on 8 yrs with a napa alternator. generally oem lasts a good amount of time, but napa is good too for parts. you can never predict when or how some parts will fail. it just happens.

Re: Flickering headlights but good alternator
 

Follow the money. His profit margin.


I worked with a guy that came from a Bosch authorized repair facility.
He said the Bosch starters and alternators came with a coupon good for one free tow.
Does that tell you anything?

I had 2 guesses:

Either they are THAT confident in their products, or
you WILL need that tow truck sooner or later.








I prefer OE, even if it is a reman.

Re: Flickering headlights but good alternator
 

i would go oem on the alt,

on the other hand i think all alternators are "hit and miss" regardless of the make, some last others dont, quality control is difficult with electronic parts

im going on 7+ years on my oem original at 250,000km

Re: Flickering headlights but good alternator
 

So to just respond on what I did and for future civic-ers in case they experience similar symptoms, I replaced the alternator and everything is now alright.

No longer do the lights flicker and no longer does my amp go out when the rpm goes up...

I did however go with the Denso alternator. Both google and people around suggested its better than Bosch. But again with electronics you might get bad apples... Just do your research always when you shell out $$$

Even though the alternator testers or DVOM readers might read the right voltage (which was my case) the diodes within tend to get hotter than usual and can't supply enough currant to the entire vehicle. And this the readers can't detect. (At least with the readers I've tested with - autoZone and other places)

Thanks to all who responded and guided me to my solution. Much appreciated.

Re: Flickering headlights but good alternator
 

Good to hear. Glad it worked out for you.