All lights pulsing

[MistorOrange]

99 civic ex , d16y8..I've had this problem for awhile , sometimes all my dash lights an over head lights as well as head lights flicker or pulse rhythmically just slight dim slight bright , repeatedly.

I've checked fuse 15 its not blown , cleaned an replaced all grounds , replaced battery harness w new OEM one , cleaned battery terminals , battery test good , an alternator test good w volt meter , puts out 14.4-14.6 , never had dead battery issues or anything , also sometimes the SRS light will flicker on an off while driving for a few minutes , really trying to exhaust everything before pulling the alt, any help appreciated , thanks

 

[5SpeedEJ6]

Have you checked the ECU? for grounds, melted cables, etc.

 

[MistorOrange]

Have you checked the ECU? for grounds, melted cables, etc.

No I'll look into that today , thanks

 

[HeX]

Have you checked the ECU? for grounds, melted cables, etc.

In addition to that, make sure your new ground wires are all making clean contact to metal surfaces.

 

[dancam]

If you figure it out make sure to let us know what it was. I have the same issue with my 7th gen at idle with headlights off. Headlights on its ok. New ground wires also. Haven't tried to diagnose mine yet tho.


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[XpL0d3r]

You don't have an aftermarket sound system, like a subwoofer / amp, do you? That would almost certainly be the cause if so.

Aftermarket accessories at all? Fog lights, etc? Sounds like something somewhere is drawing power. I know you tested the altenator, but you may want to test again while the car is under load (operating temp with AC on max and headlights on).

 

[MistorOrange]

I've had aftermarket fogs and stereo system hooked up before, to the battery, so maybe that somehow weakend the alt? Not a very strong amp just around 150 watts, but When I replaced all the grounds and battery harness, I left them unhooked incase that was causing problems, but it made no difference... ECU wires appear fine, Tested the Alt, under high load as well, rear defrost, ac max, headlights on, stereo full blast, etc, alt was still putting out what it should, no problems. I even tried something I seen online where you set your volt meter to ac and check and see if there is an "AC voltage leaking" which could be signs of a bad diode in the alt, that tested 0 like it should. Belt looks fine on the alt, never squeaks or makes any noises. When I redid the the battery and two engine grounds, I made sure paint was removed and it was bare metal contact, which made no diff in the flickering at all. Its a very strange issue, I replaced fuse 15 as well the other day just to see, made no diff, sometimes it'll just stop, they where pulsating bad last night, and i've noticed this before as well that sometimes when I hit a pot hole or a bump in the road that they stop pulsating for awhile.. dunno if its just a coincidence or what.

Thanks for all the replies an advice, i'll keep looking into it, really has me stumped, im gonna have end up just replacing the alt and seeing if that fixes, it seems

 

[XpL0d3r]

If you're hitting a bump in the road and it temporarily fixes, it does sound like some wiring issue somewhere. Hmm

This kind of reminds me of my friends old Cavalier.. he'd a bump and his dome light would turn on and then just fade away. Never figured that one out.

 

[Diana Nam]

your alternator seem to work just fine but reason why its doing that is cause your alternator is not big enough to handle all your electrics well enoughs to handle all the extra load. sound system typically uses a lot of power. all those car with some crazy audio system all have capacitors, upgraded alternators, voltage regualtors and etc so the car can handle all those electronics and not cause a potential fire also

 

[XpL0d3r]

Also, forgot to ask.. no CEL codes, right?

 

[dancam]

150 watt amp is nothing, it still does it with your amp and fog lights off right? If you havnt yet done it next time its flickering try switching different loads on and off to see if there is a difference at idle. Try from no load to all loads to just switching certain ones on and off one at a time. So, headlights, fog lights, radio/amp, rear defroster, a/c full speed, wipers, power windows... Anything else you can think of. See what happens


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[Diana Nam]

150 watt amp is nothing, it still does it with your amp and fog lights off right? If you havnt yet done it next time its flickering try switching different loads on and off to see if there is a difference at idle. Try from no load to all loads to just switching certain ones on and off one at a time. So, headlights, fog lights, radio/amp, rear defroster, a/c full speed, wipers, power windows... Anything else you can think of. See what happens


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the op has already done all that test read post #7, he even went as far as testing for AC voltage leakage and that came up as its suppose to be. i doubt his alternator is going bad at all at this point and with all the test he already did.

 

[dancam]

the op has already done all that test read post #7, he even went as far as testing for AC voltage leakage and that came up as its suppose to be. i doubt his alternator is going bad at all at this point and with all the test he already did.

He didnt, read my post again. I said nothing about checking the alternater. I know he already did that. Im asking him to check if the flickering changes with different loads. If all his lights are off and it doesn't flicker no matter how many other loads are on but it flickers as soon as headlights or tailights are on it would indicate a problem with that circuit for example.


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[Diana Nam]

He didnt, read my post again. I said nothing about checking the alternater. I know he already did that. Im asking him to check if the flickering changes with different loads. If all his lights are off and it doesn't flicker no matter how many other loads are on but it flickers as soon as headlights or tailights are on it would indicate a problem with that circuit for example.


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are you sure..... he wrote in plain English that he did and what he had turned on when hes was testing the load on the alternator. he didn't state HOW he was testing it exactly which is completely different. i know your question to the op was more of trying to find out how he was testing it.

 

[dancam]

are you sure..... he wrote in plain English that he did and what he had turned on when hes was testing the load on the alternator. he didn't state HOW he was testing it exactly which is completely different. i know your question to the op was more of trying to find out how he was testing it.

?
Im sure he understood, ill just wait for a reply. Might check a few things on my car tonight.


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[XpL0d3r]

He didnt, read my post again. I said nothing about checking the alternater. I know he already did that. Im asking him to check if the flickering changes with different loads. If all his lights are off and it doesn't flicker no matter how many other loads are on but it flickers as soon as headlights or tailights are on it would indicate a problem with that circuit for example.


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I get what you're saying. That's actually similar to an issue my car had. Car ran fine, but when I gave it any sort of load, such as turning on headlights or AC, the car would start dumping fuel.... Wideband gauge would go right to 10.0 which is the lowest it would read. It turns out that I had purchased a counterfeit Hondata MAP sensor -- it was some POS from China and there was an issue with the ground internally. It sent some f**ked up signal to my ECU apparently. New ELD, fuse box, entire engine harness later, 9+ hours at the tuner, I discovered this... lol.

SO.. switching loads could be a good idea. Measure voltage while doing so and see what happens. Hook up the amp again too. Now that we know that isn't the issue, the higher the load going to it while troubleshooting might actually be a good thing. Though I still think there's a possibility there's other wires damaged somewhere, or some sort of ground issue... pretty tough to find the cause :/

 

[MistorOrange]

Hey guys thanks for all the replies, no cel codes or anything, aside from the srs light coming on/off sometimes, rarely happens tho, and I do agree its odd that sometimes hitting a hard enough bump in the road causes the flickering to cease, I hate wiring issues like this when they come an go with no rhyme or reason lol. You'd think if it was the alt, it'd be more consistent, but maybe not. And on the suggestion of trying different loads while its doing the flickering, i'll do that again today and see/pay closer attention. I have tried that before tho to see if it makes the flickering worse, and it seems to have no effect. When I use to have my sound system hooked up, and would notice the flickering, i'd crank it up, to see if the extra draw was making it worse, but it had no effect on or off.

I've read of a service bulletin, on 96-99 civics, having an issue with wires rubbing behind the intake manifold, but I think it wasn't for the d16y8, might look into that as well. Thanks again for all the suggestions, i'll update if find something new.