Why does my car battery keep dying?

1994 CADILLAC DEVILLE
103,000 MILES • 4.9L • V8 • FWD • AUTOMATIC
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94_DEVILLE
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I have replaced the cars battery and alternator. They were both bad and I could only start my car off a good jump. However, even after replacing these parts my car still does not have any electrical power. Why could this be?
Mar 21, 2017 at 4:31 AM
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HMAC300
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check your fuses if your battery has voltage if not and battery is rung down then you need to do a parasitic draw on it. see link on how to do it.
https://www.2carpros.com/articles/car-battery-dead-overnight
Mar 21, 2017 at 5:27 AM
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94_DEVILLE
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The battery does have some voltage. As to how much, I am not sure. I do not have a multi meter or anything of the sorts. On the note of parasitic draw, is it possible that my speakers are the problem? I took the 6.5s from my Monte Carlo SS and installed them into the front doors of my Cadillac. They are both GM and have the same plugs so I assumed it would not do any harm.
Mar 22, 2017 at 4:05 AM
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94_DEVILLE
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Also, is it possible that I have a bad ground or diode? A bad diode in the alternator would explain the draining. I installed the alternator two days before I found out the battery was no good.Its to my understanding that a bad battery can cause your alternator to go bad through over work/under work. Is there any additional wiring I should check?
Mar 22, 2017 at 4:07 AM
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HMAC300
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you have to do a draw test to see what area is causing the problem. most radios will have some draw due to memory system in them
Mar 22, 2017 at 4:59 AM
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94_DEVILLE
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How would I go about doing that?
Mar 22, 2017 at 11:36 PM
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HMAC300
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you need a test light or voltmeter I already sent instructions on first reply re read it
Mar 23, 2017 at 12:13 AM
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94_DEVILLE
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If this is not the problem what else could I be looking for?
Mar 23, 2017 at 3:55 AM
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HMAC300
  • ✓Experienced Mechanic
  • 48,601 POSTS
a bad battery if no draw on it
Mar 23, 2017 at 5:00 AM
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