Lights dimming with new alternator

01yellercobra

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200amps in not very big. If you have an older sub class and amp that's making 1000WRMS, you don't have enough alternator. Hell, even if it were a newer class d amp wired to 1ohm, you'd be getting close to running out of juice.

The amp going in to protect mode has more to do with installation than music load unless you're wiring outside of mfgs rec. As long as there's airflowvand it's wired correctly, it shouldnt matter how long or loud you listen.

OP, yank the alt and have it bench tested.
It's a 500w amp. So no where near the 1000w RMS level. Everything is wired as recommended.
 

olympic

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One thing you could try is disconnecting the alternator wiring or remove the belt and see if the flickering goes away.
 

esonu

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Well removed it and had it bench tested yet everything came out good. But I think I may have found the problem. The ground that I added from the frame to the black by the oil filter seems to have a extra nut on it. So basically there’s a but then ground wire then a nut on top. Gonna try to remove it this weekend and hopefully it fixes the issue since it’s not getting good connection. Didn’t even notice it the first time around.
 

esonu

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Well removed the extra nut and put the ground directly on the block now. Alternator supposedly passed the test on the car and bench test. What do you guys recommend now. Just swap the alternator?
 

*Jay*

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I would go over all of your wiring paying special attention to any ground wire/strap you find. If that all checks out I would re-install the alternator and check function. At this point you should be much faster at swapping the alternator lol.
 

c6zhombre

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Well removed the extra nut and put the ground directly on the block now. Alternator supposedly passed the test on the car and bench test. What do you guys recommend now. Just swap the alternator?

If possible.....run by oreillys or whatever store and pick up a reman. Test it on the car see what happens. Go back and tell them it didn't fit....get your money back. If the flickering stops....you know that other alt is no good.
 

03cobra_keek

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I'm experiencing a similar issue. I switched to LED headlights and fog lights. The daytime running lights flicker on first start up then after abit they just pulse. Alternator checks out at 14.3v. I'm thinking maybe voltage regulator? I havent really looked into it yet but will soon enough
 

*Jay*

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I would swap out the lights first and see if they are bad or are on their way out.
 

03cobra_keek

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Well I did notice the regular lights would dim as well if the idle would drop from releasing the clutch. I just chalked it up as old technology lol it is an 03 and their ability then to regulate voltage isnt as good as today and havent looked any further into it yet
 

xblitzkriegx

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Well I did notice the regular lights would dim as well if the idle would drop from releasing the clutch. I just chalked it up as old technology lol it is an 03 and their ability then to regulate voltage isnt as good as today and havent looked any further into it yet
It's from 2003, not 1953. There's something else going on
 

esonu

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Well just to update the bench test and on car test passed at Autozone but I had a local shop willing to do a free check also and had them do it. They said something about the there being ac ripple with the alternator and needs to be changed. So a new one is on the way. I guess 3rd times the charm like they say for tests also lol.
 

xblitzkriegx

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Cool. My 97 Cobra still has the oem bulbs from Ford in it. They're bright, nothing flickers at all. The oem alternator lasted until last year, so 22 years. Before it failed, no weird lighting issues.

I can have the a/c on max with all the lights on and put the too down and I still don't get low voltage at idle.

My car is not some special car either. If you guys have problems, it's because something is wrong, not because "it's just old".
 

olympic

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I'm experiencing a similar issue. I switched to LED headlights and fog lights. The daytime running lights flicker on first start up then after abit they just pulse. Alternator checks out at 14.3v. I'm thinking maybe voltage regulator? I havent really looked into it yet but will soon enough

You have to disable the DRL's. The DRL module supplies a PWM 7v signal to the high beams which works great with halogen bulbs but causes LED and HID bulbs to freak out. I believe all you have to do is pull the DRL fuse under the dash to disable them.
 

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