Low voltage issue
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Low voltage issue Car is the 96 in my sig. Everytime i hit the brakes the dash lights will dim. Same thing when I turn on my heater/defroster, rear defroster, or fog lights. Anytime I do something to add current they dim/flicker. I bought a heavy duty 145 amp alternator, added a 4 guage wire from the battery to the alternator, same ****. Even read the same 13.2 - 13.5 volts running after I installed the high amp alternator when I scanned my car.
I guess I have a bad ground somewhere maybe, I dont know. Any ideas? Still seems weird that according to the pcm the new heavy duty alternator puts out the same volts as a stocker..
I guess I have a bad ground somewhere maybe, I dont know. Any ideas? Still seems weird that according to the pcm the new heavy duty alternator puts out the same volts as a stocker..
Last edited by Kevin01Z28; Jan 2, 2011 at 01:54 PM.
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From: Plain Dealing, LA
Well most automatically blame the alternator, which I replaced with brand new heavy duty unit. I added a ground strap thinking that may be the problem since I never replaced it after the wreck, didn't help. I really cant think of anything else it could be....
I think there're like, 4 grounds to deal with just off of the engine and its systems-someone correct me if I'm wrong. Don't forget the PCM has one too, I think. I would say that one of those has to be the issue...
Check the condition of the exciter wire to the alternator (small wire). It gets kinked or bent, or the connector damaged. If everything else is okay, and this wire is damaged, it will cause low charging problems. That's what the problem was with my friend's car. Sometimes it is not apparent too...look really closely.
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Check the condition of the exciter wire to the alternator (small wire). It gets kinked or bent, or the connector damaged. If everything else is okay, and this wire is damaged, it will cause low charging problems. That's what the problem was with my friend's car. Sometimes it is not apparent too...look really closely.
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Yea the exciter wire is small POS. Im still kinda stumped as to why the pcm showed the exact same reading with both alternators on my scanner... I would think that a 145 amp alt w/smaller pulley would put out more juice than the 102 amp stocker. Im gonna check the grounds and the exciter wire, but anyone think there may be a computer issue?
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Does this happen even when the car is standing still? If so, can you take out the brake light fuse (in a safe place) and then give it a try? This should isolate that electrical circuit.
Weird that this only happens when you press the brake. Does the engine bog at all?
BTW - All alternators will put out the same voltage. The difference between your alternator and the stock is amperage. They are different things and the car's PCM can't measure amps.
Weird that this only happens when you press the brake. Does the engine bog at all?
BTW - All alternators will put out the same voltage. The difference between your alternator and the stock is amperage. They are different things and the car's PCM can't measure amps.
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From: Plain Dealing, LA
I probably need to check the volts with a meter since i'm pretty sure my pcm is showing the wrong volts. The pcm only measures volts, but this same alternator on my silverado showed 14.4 volts at idle, again on the scanner not with a meter.
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I had assumed it was my alternator as well. After ordering one, I looked at the exciter, and saw that it was pretty beat up, but repairable. However, my connector is shot. Anyone know a part number or replacement for it? In the meantime, I'm splicing a new wire to the exciter, and prepping for a new connector. This has been such a hassle
