I have a 1999 Honda Accord EX Coupe with 173,000 miles. My battery light (on the dashboard) and my brake light, also my open-door lights were and still are flickering while I am driving. They don't stay on for a long time, maybe one second would be the most. I did change the alternator out and measured voltage of the battery 12.9 at idle, and 14.2 with the engine running. So it seems like battery and alternator are okay. It also seems to happen when I have my head lights turned off. Whenever I have the headlights on, I don't see this happening. Any ideas of why the lights are flickering this way? Thanks in advance for any advices.


Modified by khmr270 at 1:52 PM 11/13/2007

 

have you had your harmonic balancer checked out? the harmonic balancer went on my '91 accord and even after i had it fixed, id have problems when i used accesories (car would sputter when i turn headlights on, couldnt use heat or a/c, etc.) i came to the conclusion that the shop that fixed it originally, had done a poor job and not aligned the balancer correctly. after having it aligned, everything was good. maybe your balancer is ready to go. idk just a suggestion

 

What is that and where is it located? Forgive me for I am not a mechanic. I'm just trying to see if this is something I can attempt to fix myself. Thank you for your suggestions. Hopefully I'll get more suggestions

 

was it a factory alt or vatozone aftermarket ?

 

the harmonic balancer is a thing that is usually attached to the crankshaft pulley (one of the wheels that the belts ride in). the harmonic balancer (HB from now on cuz i dont feel like typing over and over again) helps keep the vibration from the crankshaft to a minimum. the crankshaft twists and bends everytime a cylinder fires, and the HB helps to deflect the tension. if the HB goes bad, it can throw the whole belt system off balance. i am not positive this is your problem but the symptoms sound similar to when my HB went bad

 

Hmm.. 12.9V at idle, that's really low.. 14.2V with the car running??.. Uhh, are you sure you have 12.9V at idle? Because you stated that you have 14.2V with the car running. The car is also suppose to be running at idle. Maybe you meant 14.2V with the head lights and AC on.

What I usually do if I am dealing with a charging system problem. I usually let the run and idle for a few minutes and then check the voltage at idle. I'm usually looking for at least 14V to 14.3V. Then I turn on the head lights and AC and check voltage again. I should have at least 14V to 14.5V. If not, I pull out my alternator tester and go at it.

You have to remember that a failing battery will force your alternator to not charge properly. And a failing battery will sometimes cause your alternator to fail. I usually replace them in pairs for those reasons.

But an easy to check if your alternator is working correctly to do the above voltage test. If your readings are a little low, I usually hook up a jumper pack or "Good" car battery. If the voltage readings jump up to 14V to 14.5V at idle and with loads, then it's most likely your battery that's causing your alternator to not charge properly.

 

I have had this exact same problem on my 1999 Accord V6 Sedan. The original Delphi alternator had gone bad, so I replaced it with what I could get my hands on in a pinch - a Palladium alternator from Advanced Auto. It lasted for a short time. The regulator gave out and basically caused my battery to "boil". The alternator was putting out over 16V. I replaced the alternator with another one under warranty. Other than adding distilled water to the battery, I did nothing with it. From the time I replaced the alternator with this new one, I had the flickering lights in the dash problem. I found it usually occurred when I decelerated - as you would approaching a stop light or turn. Because these alternators have the ability to be turned on and off by the ECU, I was sure that either the high voltage from the failed alternator spiked and damaged the ECU or the turn on/off point of the new alternator was not the same as OEM. I monitored the battery voltage as I was driving and also noted the voltage dropped to ~12.9V when the lights would come on.

I had taken the car to the auto parts store where they perfomed their vehicle alternator and battery test. I was told the battery was performing fine. They did note the anomally with the voltage dropping when the accelerator was released. They felt the new alternator was defective and offered to replace it again. I took them up on the offer and replaced it again. The problem remained and has been present until I read this thread. Today I replaced the battery that I was told was good. It resolved my issue. I cannot explain why it made a difference, but it certainly did.

Thanks for your post PnX-R, and to khmr270, give the new battery a try. It fixed mine.