battery light on

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medgraphsho

Bill T.
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My battery light just came on this morning. Could it be alt. or battery or both? The dash dimmed a little when the light came on. Now when I accelarate the light starts to fade and eventually goes out at highway speeds then starts to light up as I come to a stop. So, Im thinking altenator. Guess I could go get it tested at autozone???
 

Sammy~D

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get them both tested while you are at it but make them do the long test on the battary cause if it is only your alt the batt will be low and it will fail out
 
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from my experience, if it is the altenator your car will eventually die when the battery finally drains. when it happened in my 94. I just bought a new altenator and battery, then i was good to go
 
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gen 3 or gen 2? never done it on a gen 3 so i really couldn't tell you, the gen 2 was alot easier than i thought it would be
 

SHOZ123

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Alternator. The battery light comes on when the battery voltage is higher than the alternator output voltage.
 

hawkeye18

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Alternator. The battery light comes on when the battery voltage is higher than the alternator output voltage.

That's true 90% of the time, but that's not the only reason it'll come on. It's a simple differential circuit; it will come on when either source is ~2V higher or lower than the other. (it takes about 2v to start lighting the bulb up)

I agree though, it's more than likely your alternator. They go bad far more often than batteries do on these cars (unless the alternator kills the battery lol).

On a gen 2 ATX, I can change an alternator in 15 minutes, from hood up to hood down. The MTXs I would imagine would take about twice as long, depending on how rusty your tensioner is. It's still pretty darn easy.
 

sperold

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Shop around and see if you can get an alternator with a lifetime guarantee (there is such a thing). I got one of these deals at a garage near my place and it came in handy a year later when it failed.
 

badcamelot

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alt change

The gen2 alternators on atx's are pretty simple. 4 bolts (13mm) and I think the serp belt tensioner is 18mm. You will have to remove the idler pulley to remove the bottom bolt on the alternator. As mentioned it is pretty easy.
My starter was apparently draining my battery so bad that after several starts the alternator couldnt replace the charge in the batt quick enough (I do alot of starting and stopping) - at least thats what i believe. I replaced the abtt with an optima battery. It still went dead a couple of days later. Changed the alternator. Still went dead. Then changed the starter because a mechanic told me that although rare, starters can apparently draw far too much amperage during the cranking start cycle and literally drain batterys dead, so much so that an alternator cannot usually re-charge the battery. I thought this was a stretch, but so far it has proven to have solved my battery drain problem.
Sounds as though in your case it's just your alternator. Most places, when I called around for prices, offer the lifetime warranty -well 'limited' lifetime - meaning if it fails for reasons related to the alternator itself it's covered, but external damage no.
Good luck.
 

kay077

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what is the correct alternator for a 1994 SHO with a 3.2L motor. i have change 5 alternators sinice i got this car 5 years ago. Will appreciate na input
 

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