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Buick running at 10V, dies at 8V

I have a '99 Buick LeSabre and I know there are some electrical problems (i.e., radio randomly spits out cd’s that aren’t in; when in park, the headlights randomly come on and go off again; automatic windows choose when the want to work, etc.).
Recently, while driving home from work down a dark highway, my lights dimmed, my battery gauge dropped and my defroster stopped blowing. I found the first turnoff and waited for my brother to come. While he had my crank it so he could see, it died completely. Hazard lights wouldn’t even work. We charged it for a little and I made it about a half mile up the road, then it died on my completely again (again, not even enough juice for interior light). We charged a little more to get me off the road again, and I got another half mile and pulled over before it had a chance to die again. We charged for maybe 20 minutes and that got me the remainder of the way home (approx. 8 miles). The next day, I purchased a used (supposedly rebuilt) alternator from a salvage yard and installed it. Everything seemed to be going well for a week (to the day).
Last night, on my way home from work, I noticed the battery gauge was on 10V. My car never died, but my blinkers would barely blink (one of my first signs last week) and it definitely made me nervous the last six miles of my drive. I refrained from any more blinkers, turned off defroster and radio and used only my headlights the rest of the ride, but my needle didn’t move. I’m a girl who doesn’t know much about cars, but the way it was put to me was this: with the battery being 12V and the alt. being 14V, my car should run at 14V give or take one or two depending on how many “luxuries” I had on at the time.
My questions are these: Is it possible that I bought another bad alternator? Or that the previous bad alternator killed my battery cells? But if my cells were dead, wouldn’t it not juice the alternator to initially start? Then shouldn’t I still be running at 14V? I’m not stupid, I’m just uneducated on mechanics, but I am teachable. I have a variable income (part-time waitress) and 6 children dependent on me, so there is no room in our lack-of-budget for car repairs. Is there something I can do or VERY cheaply have done to fix my problem(s). I need this hoopty running smooth again, as it literally is our lifeline. Please help.

Was the battery recharged prior to installing the replacement alternator? If not that may have damaged the replacement alternator. Alternators aren’t designed to recharge discharged batteries. This can cause the alternator to run hot damaging components inside the alternator.

When I purchase remanufactured alternators, this is the warning that comes with them.


Take the car to a store like Autozone and they will check out the charging system at no charge to you in the hope they can sell you something to fix the trouble.

It sounds like you initially had a bad alternator but you may also have a bad battery. A defective battery can cause damage to the alternator. Make sure the large wire coming from the alternator is making good connection to the positive battery post. You can measure the voltage between those points while the engine is running and have the lights and blower on high. If the connection is good you should see less than .3 volts between the connection points.

The other intermittent problems you talked about may be due to a intermittent connection problem in the fuse panel under the hood.

Buy a new battery and have all connections cleaned,

It is possible your non charging old alternator finished off the battery in the process. You can buy a charger and hook it up and recharge the battery fully. But, I’d have the battery load tested (Advanced Auto, or Auto Zone) by your local mechanic or parts store. If the battery in the car is 5+ years old you might just replace it and see what happens. A battery at that age could simply be due for replacement.

You can also have the output of the new (rebuilt) alternator tested. The alternator could be OK but an old battery won’t hold a charge very long.

Since skills and money is an issue, maybe we can work at this in the most basic of procedures.
Does the little red battery light on the dash illuminate when the key is in the RUN position?
It must, or the alternator will not charge.

If the light does illuminate, leave the key in the RUN position (engine not operating), and lightly touch the pulley on the alternator with the tip of a screwdriver, etc. You should feel a magnetic attraction by the pulley.

A magnetic attraction (while not always foolproof) is generally a sign that the alternator will charge and you should consider the possibility of a fault in the alternator to battery wire leads. A good place to start would be to inspect the junction terminal near the battery where the battery positive cable brances off and provides all electrical power to the car. It could be that the connection there has become corroded and contact lost due to age and repeated heating and cooling cycles.

One thing you cannot do is drive around even with 12 volts showing because that will assuredly leave you stranded at some point. In the old days of carburetors and contact point distributors one could drive a car clean across a large state with no alternator at all but modern cars will not allow this.

First off, any good independent mechanic can fix you up. This should prove easy – although possibly semi-expensive-- to fix. That’s the best way to get your car back on the road. Want to do it that way? Then ask friends, relatives etc for a recommendation.

The cheapest way to determine what’s causing this is to go to a big box auto parts/service store like Sears etc. They will often diagnose your battery and charging system for free. They do this because they know from experience they’ll likely sell the customer a battery. Not a scam, just that customers often need new batteries. Batteries usually last about 5 years, then the first cold day, wham, the car won’t start or it doesn’t charge up the battery like it should.

A running car with a battery at least 50% charged would normally show 13.5 to 14.5 volts. 12-12.5 volts when not running. 10 volts means there is something definitely wrong. It could be a bad alternator or a bad battery or something else wrong that is putting a load on the electrical system.

Home mechanics who work on their own cars on the cheap usually have their own DVM, battery charger, and a gadget that measures the density of the battery electrolyte. And a battery post cleaning tool. If you want to tackle this yourself, you’ll probably need to move in that direction. Otherwise you’ll need a shop with the proper tools to help you.

Thanks for your help, y’all. The problem was that some of the wires had come loose from the clamp that attaches it to the postive battery terminal. Though my car is purring along now, it begs the further question: could that have been the original reason my alternator went bad?

Yes. that is quite likely.
An alternator is supposed to have the battery attached.