Best Answer
TestBefore paying money for a new alternator (which I was about to do today), be sure to have the alternator tested. As many people suggest, Auto Zone, and other parts suppliers, will test it for free. You may have bad connections into your alternator...make sure they are secure and free of corrosion. You might also simply need to tighten the alternator belt. A loose belt will also prevent the alternator from charging the battery. Cable testTry this: With the vehicle running, disconnect the negative cable from the battery. If the vehicle keeps running, the battery could be bad. If the vehicle dies, the alternator is probably bad. Most major auto parts stores can test batteries and alternators.

Note - the above answer states that you should disconnect the negative cable from the battery. 'The correct answer is to remove the POSITIVE cable not the NEGATIVE.

constantly deadYour battery is there for starting purposes only- once you start the car, the alternator/generator takes over, and runs the cars electrical system (and recharges the battery)- if you start your car and then disconnect the battery, if your alternator is good, the car will keep running. bad alternator and the car will die. note that if your alternator is bad, your car can run off the battery for a while till the battery dies. sure sign of bad alternator = constantly dead battery. Additional Answers
  • start the car the remove positive battery terminal if car stalls or idle drops really low alternator is bad
  • My battery indicator light came on, but the car would still start and the alternator belt was intact. I tested the alternator with a volt meter and sure enough it was bad.
  • Battery continually going dead. Best thing to do is drive the car to an Auto Parts store and have the alternator load tested.
  • If you do not have a voltage tester bring it to a repair shop and have them test the alternator. Puts out between 13-14 volts. If under 13 it is probably bad
  • You can always start the vehicle and disconnect the battery. If it dies, your alternator is the problem. If not something else might be the problem.
  • start or jump-start the vehicle. Remove jumper cables after it's started. Use a volt meter to find out the voltage at the battery. If it's below 13.5 VDC, the alternator is probably bad. Take it to an auto parts retailer and they'll usually test it for free.
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โˆ™ 2014-07-30 15:12:36
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Q: How do you know if the alternator is bad?
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Related questions

How do you know you have a bad alternator?

Turn car on remove positive battery terminal if car turns off alternator is bad

How do you know when the alternator is going bad?

When your battery does not get charge.

How do you know when alternator is bad?

Typically you know your alternator is out when you have to jump start your car numerous times. A way you can test it is by turning on your car and while it's running discount the + terminal. If the car turns off then your alternator is bad. If the car remains in then alternator is good and possible bad battery. Hope this helps

How do you know if your alternator is bad?

If it is makeing a noise or is not putting out at least 13.5 volts it is bad. Take the car or the alternator to an Auto Parts store and have them load test the alternator to be sure.

What causes your alternator not to charge?

A bad belt, a bad regulator in the alternator or bad brushes in the alternator.

How do you know if alternator fuse is bad?

If the alternator fuse is bad, the alternator is not going to work properly to charge the battery. An alternator runs off the serpentine belt, with graphite brushes inside that conduct electricity to charge the battery.

How do you know if 2004 dodge ram 1500 alternator is bad?

with vehicle running pull posative side battery terminal off if it quits alternator is bad

I have a 2003 Chevy impala how do i know if i have a bad battery or bad alternator?

To test the alternator if funds are low, let the motor idle and remove the negative battery cable, if the motor dies its probably the alternator.

How do you know if an alternator is bad?

Check voltage with a voltmeter at the battery With engine running readings should be 13.8-14.2 With engine running hold a screw driver to the back of the alternator, if there is no magnetic field, the alternator is bad.

How do know when alternator is bad?

If your talking about cars... If you smell a burning smell, or your red battery light comes on then i would get your alternator checked out!

Why isn't your Mazda truck alternator not charging your battery?

bad alternator, bad voltage regulator, bad battery, bad connections.

How to know the alternator is bad on 2003 Chevy Malibu?

You can have it tested at a auto pars store like autoZone. Another symptom is that if it has power issues, its the alternator I have the 03 LS and it needs a new alternator.

How do you know if your alternator is bad on an 85 Pontiac fierro?

advanced auto parts stores can check it for you

How do you know if your alternator is bad in your 1996 Oldsmobile aurora?

A warning light on the dash would illuminate.

Can the bad alternator cause the water pump to good bad?

The alternator is belt driven and so is the water pump but that is where the correlation ends. There is no way a bad alternator could cause a water pump to go bad unless the alternator pulley was warped. Then there is a small chance.

Why wont alternator charge on a 1968 bug?

alternator is bad

Do bad spark plugs have to do with charging the alternator?

Spark Plugs do not affect your alternator. As long as your engine is running then it should be charging unless your alternator is bad

Will a bad ground wire ruin an alternator?

a bad ground wire can ruin an alternator by not completing the circuit

What are signs of a bad alternator?

Start the vehicle then disconnect the battery. If the motor dies, you probably have a bad alternator.

What are the signs of a bad alternator in a Ford Expedtion?

A bad alternator will not give proper power to the vehicle. Dim lights, buzz in the stereo or a dead battery could all be causes of a bad alternator.

How do you know if you have a bad alternator on a 1999 Monte Carlo?

go to autozone and get a free charging system check.

How do you know if your altinater as gone in your car?

If your battery doesn't hold a charge while running then your alternator is bad

How to know if the alternator is gone in a 98 mercury mystique?

let the car run and then pull the negative battery cable off. if the car stalls, the alternator is bad! do you know where the bank 1 o2 sensor 2 is?

What will cause my old and new alternator in my 98 frontier to not charge?

bad alternator cable/corrosion bad battery

What makes the alternator sensor fuse blow?

it can be caused by a bad alternator

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