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How you diagnose difference between Alternator Starter or Battery going bad in a 1999 Volkswagon Passat?
Wiki User
∙ 18y ago
Will it "jump start"? If so, it's not the starter. If not, it could be starter, cable or other wiring problems. If it will start using a "jump start", you probably have either a loose or corroded battery connection or your battery isn't fully charged. If it's not fully charged it can be either a bad battery or the alternator. If you can't take it someplace to have the battery tested, try this simple alternator test: Jump-start the vehicle then remove the jumper cables. Borrow, rent or buy a volt meter and test the voltage at the battery. With the engine running at around 1000 to 1500 RPM, your meter should read about 13.5 Volts, +/- a half a volt. If it's close to that, have someone keep the engine running then turn on some of the accessories that draw the most current, such as the heater motor, headlights and rear window defroster. The voltage shouldn't drop with all of those accessories running. If the voltage drops below about 13 V under load, you probably have an alternator problem.
Wiki User
∙ 18y ago
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How do you diagnose bad alternator?
Start the truck then disconnect the battery if it's still running the alternator is good
Diagnose battery charging failures 191 crx si?
May be your alternator.
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most likely the start of the alternator going bad.
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Start by making sure the battery itself is good. If the battery is good, then you more than likely have a defective alternator. Any auto parts store can diagnose the problem.
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Your alternator is probably rebuilt and not really new. I have had this problem several times and I have bought a new battery and alternator. The alternator keeps your battery charged and powers your electrical system, so even when driving you can lose all power in the car from the alternator draining your battery. Take the battery and alternator to an auto store and they will test both for free. Ask them about the difference in a rebuilt alternator and a brand new one. This is a very common problem.
How do you know the difference between needing a new alternator or battery for your car?
Test the battery at a local place such as advanced auto. They do it free.
Can a car battery be damaged with a falty alternator?
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1998 Chevrolet Cavalier Daytime Running Lights troubleshooting.?
my 05' cavalier has a bad alternator problem its charging the battery a little bit then stops and the little power my battery has is drained by the end of the night. I replaced the alternator twice and the battery but still no difference.
Why will my 1997 Isuzu Rodeos battery not charge?
Order of likelihood: 1. Alternator 2. Voltage regulator (probably built into the alternator 3. Battery 4. Wiring and/or connections in charging system. Visit a major chain auto parts dealer and they will diagnose the problem free of charge,. If you need and buy a new battery, they will install it at no additioal charge.
How do you wire alternator to a battery to test alternator?
run it and then disconnect the negative wire from the battery if alternator dies its bad.
What does your alternator do?
an alternator recharges the battery of your car
How can I test my alternator to see if it is discharging my battery?
You can have the alternator tested free of charge at just about any major auto parts store. By the way, a bad alternator will not "discharge" a battery - the alternator's function is to provide the charge to the battery. If the alternator is faulty, then it is not providing the charge necessary to keep other components from discharging the battery. I had the alternator tested and it was charging. If the alternator has a bad diode, it will discharge the battery. I replaced the alternator and everything is fine.
