Battery light

[Francos Accord]

Recently my alternator died on me, so i replaced it. Now, being 2 almost 3 weeks after, my battery light occasionally starts to come on and flash at me when all i have on in the car is the radio and my headlights, but other times i will have my fogs and my defroster on too. Can anyone tell me whats going on?

[carotman]

you replaced it by a brand new unit?

[Francos Accord]

Yea, got it at autozone. I even when back and had them test the battery. they tested it with the car off, and then turned the car on to see if the alternator was charging it. It was. They said it was like a brand new battery in the car... Im stumped :confused:

[turabaka]

Is the ground strap secured nice and tight on the alternator. I know mine came on once because that ground wasn't tightened all the way.

[Francos Accord]

Yea, it is, when i got it in, i double checked everything was tight. Nothing was loose...

[carotman]

This might be of some help:

http://www.rowand.net/Shop/Tech/AlternatorGeneratorTheory.htm


Dashboard Indicator Light

If you have an alternator and are using the factory style indicator light on your dashboard, it is a pretty helpful thing. It helps kick-start the alternator into working at idle speeds when you first start the car, and it tells you if the alternator is putting out less voltage than the battery has in it, indicating a problem. The light is connected on one side to the field current system inside the alternator and to a switched ignition power source on the other side. When you turn the key on but have not started the car yet, the field acts as a ground and power flows through the light and out to ground - lighting the bulb so you know it works. Once you start the car, the voltage at the field is powered internally by the output of the alternator. If this value is exactly the same as the battery voltage, then you have the exact same voltage on each side of the indicator light and they balance each other out - kind of like a tug of war in reverse. If all goes well, the light never comes on, and you drive happily around knowing all is well with your alternator. If the output of the alternator should drop due to a slipping/broken belt or due to certain kinds of electrical faults inside the alternator itself, there will be less voltage on the field side of the light and more voltage on the switched ignition side of the light. The result is that some amount of electricity will flow through the light and into the field and the light will glow proportional to that voltage difference. This is how a slipping belt or an overloaded alternator will cause the light to glow very dimly, while a full-on failure will cause the light to glow very brightly. Note that if you disconnect (or forget to connect) the wire at the alternator, the light will never come on and the alternator will not charge properly.

The dashboard indicator light circuit also typically has an extra wire with a calibrated resistance in it. This wire is run in parallel to the indicator light and has about a 10ohm resistance. It's purpose is to allow slightly more current to flow to the alternator field current system at initial start-up to make sure the alternator begins producing power as soon as the engine starts. About 1 amp total current is flowing to the field current between the light and the resistance wire, with the resistance wire supplying about 3/4 of an amp. This extra resistance wire does not affect the functionality of the indicator light in any way.

If the light come on, this means something is wrong with the wiring or the alternator itself. The alternator can give enough voltage but can't provide enough current (amperes) and then the voltage drops, making the warning light come on.

[Hauntd ca3]

i'd suggest getting a voltmeter and checking he output voltage of the alt with all acc except the wipers going.
lights on high beam , heater on full, ac on etc.
bring the revs up to round 2000-2500 and it should be between 13.5 and 14.3 volts.
if its above but still close to 13.5v its likely to have a brush or regulator prob.
if its below 13.5, take it back.
af its above 14.5, ditto.
to low of a voltage suggests that the alt is crankin out heap of amps all the time, which is bad.
it fries rectifiers,slip rings,brushes and can blow the reg because of the high field current for an extended period.
you dont say if you've got efi or not tho.
if you do, output voltage is controlled by the ecu, hence the 4 pin plug on the alt.
efi voltage will vary between batt voltage and up to 15.2v depending on what the ecu decides it wants.

[LX-incredible]

Our alts are not ecu controlled, the 4th wire is just an input to the ecu. White/red AGS wire goes straight to the fusebox, unlike later cars where it comes directly from the ecu.

Everything else looks spot on. More than likely vatozone sold you a shit alternator.

[Bluntman]

Autozones rebuilders are crap. Never buy starters, alts etc. from them. Napa builds are quality. I believe Autozone was Chief auto parts back in the day, which sucked big time.

Autozone did aquire chiefs in 98. And Chiefs was the worst place ever!
http://www.nytimes.com/1998/05/12/business/company-news-autozone-plans-to-buy-chief-auto-parts.html

[MessyHonda]

Autozones rebuilders are crap. Never buy starters, alts etc. from them. Napa builds are quality. I believe Autozone was Chief auto parts back in the day, which sucked big time.

Autozone did aquire chiefs in 98. And Chiefs was the worst place ever!
http://www.nytimes.com/1998/05/12/business/company-news-autozone-plans-to-buy-chief-auto-parts.html

yup i used the napa performance alternator....it even pumps out 77amps at like 5000rpms

[jdmca6]

that happened to me too.
turns out that the positive side of the battery was rubbing against my hood while driving to the point were it rubbed off the paint and it was sparking lol
i got that plastic isulation thingy and it was gone.
:blah:
prob diff problem than urs tho

[Ayeobe]

Hah this ones funny..
In november and december last year, my car was sometimes unable to charge properly at 800rpm... It would dim down like crazy, but if i revved it up, it would work fine again (revv to 1000-1500rpm)

Then suddenly, it went back to normal. like nothin ever hapened.
My dome light did the same.. never worked, then when i decided i'd start pullin shit to figure it out... ta-daa...it light right up!

Anyway, good luck with yours, as it dosnt seem to be fixin itself. Hopefuly if its the altornator, they'll take it back..