Alternator Failed Then Started Working Again

Dan Ferrell writes well-nigh do-it-yourself auto maintenance and repair. He has certifications in automation and control technology.

The alternator is at the eye of the charging system of your vehicle.

Photo courtesy of Pentti Immonen on Wikimedia

Alternator problems and charging system problems tin affect your vehicle in dissimilar means. Y'all may notice:

• your ALT or Charge indicator light comes on,
• your engine is hard to start and cranks slowly, or doesn't crank,
• your battery demands lots of water,
• your alternator makes noises,
• or your headlights suddenly get dim.

These and other problems may exist acquired by a error in the charging system.

Before you lot get-go replacing components with the hope of fixing the trouble, you need to make up one's mind which component or components are causing yous trouble. Often, it is possible to diagnose and solve the problem on your ain using a few unproblematic tests and tools.

The sooner yous observe out what is causing trouble, the better. Yous'll forbid a faulty component from ruining other parts in the system, which would make your repair more than expensive.

This convenient troubleshooting guide volition assistance y'all find out what you need to know, using a few unproblematic checks you can practise at abode using a test light or digital multimeter (DMM) and peradventure a few other mutual tools.

It is a good thought to have on mitt the vehicle repair transmission (or a good aftermarket manual) for your item machine make and model. Information technology will help yous identify wires, specific components, and mayhap suggest some specific tests recommended by your manufacturer.

If you want to test the status of the system as a diagnostic starting point, do the tests described in the following section, "General Charging System Bank check."

However, if you lot need assist for a specific problem with your charging arrangement—for example, an over-accuse or under-accuse status, discharging battery, or noisy system—then skip over to the "Charging Arrangement Problems and Potential Causes" section.

Index
I. Mutual Symptoms of a Bad Alternator or Charging System
2. General Charging System Checks
III. Charging System Issues and Potential Causes
Four. Troubleshooting for Unusual Voltage System Drops

The battery indicator should plow off when your engine is running.

Photo courtesy of Kskhh on Wikipedia

I. Mutual Symptoms of a Bad Alternator or Charging System

Indicator Light On

Usually, the get-go sign that your charging system is in trouble is a "bombardment," "ALT," or "Accuse" warning calorie-free illuminating on your instrument panel while driving. It means that the alternator voltage output is below 12 volts, or over its limit or has stopped charging the battery and your motorcar is running on battery power.

If the light illuminates only intermittently, it usually indicates a loose or worn bulldoze belt or serpentine chugalug, worn-out or bad carbon brushes in the alternator. Just remember that the light doesn't e'er mean at that place is a bad part; the light may be triggered by a sensor giving a wrong message or there'south something wrong with the circuit itself.

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Engine Cranks Slowly, Doesn't Crank or Stalls

When the battery is undercharged, you may have difficulty starting the vehicle, the engine cranks slowly or doesn't creepo at all. Too, the engine may stall if the alternator tin can't produce plenty power to run the ignition system. Become over the next section on "Full general Charging System Checks," and, if necessary, cheque the section "4. Troubleshooting for Unusual Charging Arrangement Voltage Drops." further downwards in this article.

Battery Overheating and Using Too Much Water

An overcharged bombardment causes the bombardment to overheat. You discover yourself calculation h2o to the battery frequently. If the trouble is non taken care of on fourth dimension, it can ruin your battery. Also going through the side by side section, make certain to check section Iv below on "Troubleshooting for Unusual Charging System Voltage Drops"

Noises Under the Hood

Squealing, buzzing or grinding noises coming from the engine may be caused past bad alternator components, a loose or worn-out serpentine belt, or a faulty belt tensioner, loose alternator pulley or mounting bolts, worn bearings, or faulty diodes. Run into the "Checking for Alternator Noises" subsection further down in this article.

Dimming Lights

If you find the headlights, musical instrument panel, or interior lights dimming or flickering, ability windows running boring, radio or gauges don't operate equally they should, either your battery has a low accuse, or there's one or more faulty diodes within the alternator. Cheque your battery and see the "Alternator Air conditioning Voltage Leak Bank check" subsection further down in this article.

Check the drive chugalug for adjustment and tensioner for proper operation.

Photograph courtesy of Una Smith on Wikimedia

Two. Half-dozen Tests for the Charging System in Full general

These series of charging organisation checks assistance diagnose the general condition of your charging system. They can help y'all ostend that you actually have a problem in your charging organization and locate the source of the problem.

one. Brand a Visual Inspection of the System

With the engine off, popular the hood open and visually inspect the different components of the charging system. Look for a worn out or loose drive belt, alternator connexion issues, loose alternator mounting bolts, and corrosion and dirt around the battery case and cables.

When inspecting the drive belt, check for adjustment. If necessary, adjust the belt with the assistance of your machine owner's transmission or repair manual. Inspect the belt for signs of cracks, cuts, shiny spots, deterioration or other signs of wear or impairment. Change the chugalug and belt tensioner at the manufacturer's recommended interval.

2. Bank check for Wiring Problems

Inspect the wires and connections at the dorsum of the alternator, at the remote voltage regulator (if applicable), and at the battery. Look for corrosion at the connectors, damaged wires, and burned and missing insulation that might suggest an electrical short.

iii. Do This If the Indicator Light Stays On, or Goes On and Off

Follow the next steps:

• Start the engine and apply the emergency brakes. Set the transmission to Neutral (transmission) or Park (automated).
• Connect a voltmeter across the battery terminals.
• While watching the voltmeter display, start wiggling wires at the back of the alternator, the battery, and the remote voltage regulator (if in that location is ane).
• If the voltage reading on the meter display goes up while wiggling one of the wires, you lot've found a bad electrical wire or connectedness.

Instead of using a voltmeter, you can have an assistant watch the indicator light on the musical instrument panel to see if it turns off as you wiggle diverse wires and connectors. One time the light turns off, you've found the problem connector or wire.

iv. Bank check for Alternator Noises

Bad alternator bearings, rectifiers, rotor shaft, stator winding, slip rings, brushes and other parts inside the alternator with mechanical or electrical issues can become noisy.

Here's a exam you tin exercise: Use a length of vacuum hose to mind for alternator noises. The hose will dilate the noise if information technology'south coming from the alternator. Simply exist very careful around moving parts while y'all do this test.

• Start the engine.
• Place one finish of the hose against your ear and move the other cease around different points of the alternator trunk.
• Heed for whining noises (this can indicate a bad diode or an over-charging status), grinding (bad bearing), squealing, or other abnormal noise. If necessary, have your alternator checked.

5. Bank check for Under-Charging and Over-Charging

The side by side iii tests are best washed using a load tester, but you however can use your digital voltmeter. Y'all exercise this by measuring organisation voltage while loading the system.

5a. Offset, measure bombardment base voltage to make sure you have a fully charged battery.

• Turn on the high beams for 10 seconds so turn them off.
• Wait for two minutes
• Mensurate bombardment voltage across the battery posts with your DMM. You should get between 12.4 and 12.6V. This means your bombardment is fully charged. If you go a reading below 12.4V, charge the bombardment before standing.

5b. Measure the Charging System'southward No-Load Voltage

• Ask an assistant to start the engine and concur engine speed at about 1500 RPM.
• Measure out voltage across the battery with your DMM. Y'all should get 0.5 to 2 volts college than base voltage. If yous are getting more ii volts above base voltage, well-nigh probable your alternator is over-charging the battery or the bombardment is faulty. Other potential problems are a faulty voltage regulator or a trouble in the charging system wiring. As part of your wiring checks, meet the section "Troubleshooting for Unusual Charging System Voltage Drops" below.

5c. Mensurate charging system load voltage with a high-electric current-condition organisation measurement.

• Enquire an assistant to commencement the engine and hold engine speed at about 2000 RPM. Plow on all electrical accessories like A/C, blower motor, headlights, defroster, wipers. But don't turn on the heated windshield if your vehicle has one; alternator voltage may increase to over 100V and this can exist unsafe.
• Have a voltage reading across the bombardment posts. Your reading should be at least 0.five volts higher up base voltage for your system to keep upwardly with electrical system demands. Otherwise, the charging system can't encounter the demand and charge your battery. This fault could indicate to a faulty alternator or voltage regulator. Check the department "Troubleshooting for Unusual Charging Arrangement Voltage Drops" below to cheque for wiring bug that can lead to this condition.
• NOTE: These measurements correspond to an ambience temperature of nigh 70º F. The charging voltage will increase as temperature drops, and charging voltage volition decrease as temperature goes up. And then keep this in mind when making your measurements.

half dozen. Check for Alternator Air-conditioning Voltage Leak

Alternators use diodes to rectify alternating current produced by the alternator into straight current. When i or more than diodes go bad or a stator winding fails, the alternator can cause all kinds of problems. Air-conditioning voltage leak can cause your lights to dim and bleed ability from your bombardment, for example. Usually, yous can notice this leak by measuring AC voltage at the alternator.

• Showtime and let the engine idle.
• Set the parking restriction and your transmission to Park (automatic) or Neutral (manual).
• Fix your meter to a low Ac voltage range.
• Ask an banana to increment engine RPM to 2000 rpm.
• Touch the cherry meter atomic number 82 to the alternator battery terminal B+.
• Affect the blackness meter lead to the alternator case (ground).
• If your DMM reads 0.4 AC volts or less, the diodes are good.
• If your DMM reads 0.5 Ac volts or more, the diodes or stator is faulty.

Once you've adamant the condition of the arrangement, yous tin go over the adjacent section to nada in on the potential trouble(s) that may be causing the condition of the charging organization.

A unmarried bad bombardment prison cell can prevent your charging system from working properly.

Photograph in the public domain.

III. Charging System Issues and Potential Causes

To speed upwardly your diagnosis and repair, look upwards the arrangement condition that most resembles your trouble and become over the potential causes described nether that condition. Some checks or tests may be suggested as appropriate.

1. If the Battery Seems to Stay Undercharged

You have already charged your battery a couple of times and you just establish out the battery is undercharged again. Before y'all blame your battery, or the alternator, here are some preliminary checks you may want to do.

a) Check the bulldoze belt or serpentine chugalug, specially if you haven't replaced it in the final five years. Make sure the belt has the proper tension. Look for signs of wear or damage like cuts, shiny spots, missing chunks. Today serpentine belts don't bear witness signs of article of clothing, fifty-fifty if they demand to be replaced. Utilise a belt wear indicator or check your maintenance schedule for the replacement interval suggested by your machine manufacturer. You may find the schedule in your car owner'south manual or your repair manual.

b) Along with the drive belt, cheque the belt tensioner as well. Brand certain it turns freely and is racket-costless. Car manufacturers recommend replacing the tensioner at the same time you supercede the drive belt.

c) Make sure your battery connections are tight and clean. However, just because the terminals look clean, it doesn't hateful they are tight and in adept condition. Look for damage to the cable and the terminal itself that may forestall proper electrical current period.

d) Check your bombardment yourself, or take information technology to your local automobile parts shop. Many of these stores will test your battery for free.

e) There's a parasitic bombardment drain stealing ability from your battery.

• A quick test is to connect a test low-cal in serial between the positive bombardment cable and the positive bombardment mail service. If the examination light comes on, there is an electric bleed in 1 of the systems.
• First, unplug the alternator electrical connector. If the test light goes out, the alternator is causing the drain. If non, locate the parasitic drain.

f) Don't overlook the starter motor: a failing starter motor may depict excessive electric current during performance, draining bombardment power. If necessary, have your starter motor or starting organisation tested.

k) If you recently added an electrical accessory to the vehicle, you may have over passed your alternator's capacity.

h) At that place could be an alternator wiring problem.

i) Have the alternator and battery checked.

2. If the Organization Seems to Exist Over-Charging

As well test results, another potential sign that your bombardment is being overcharged is that your battery terminals proceed accumulating corrosion.

Here are some checks yous desire to practise:

• Brand sure that all the connections to the alternator, remote voltage regulator (if applicable) and battery are clean, tight and in good condition.
• Check your battery or accept it tested at your local machine parts shop. A bad battery cell can cause the alternator to over-charge the skilful battery cells.
• Cheque for a bad alternator voltage regulator and circuit. Consult your vehicle repair manual, if necessary.
• Make certain y'all have expert ground connections at the alternator (alternator case) and voltage regulator, peculiarly if your vehicle uses a remote voltage regulator. Grounds should be free of rust, and the alternator and remote voltage regulator mounting bolts should exist clean and tight.
• Check the alternator rectifier or take your alternator checked at the auto parts store.
• Also, conduct the tests described in the Troubleshooting for Unusual Charging System Voltage Drops below.

3. If the Alternator Is Non Charging the Battery

When your tests indicate to an nether-charge or no-charging condition:

• Make sure the drive belt is not loose or worn out.
• If necessary, borrow a good battery just to operate the engine and confirm that your drive belt and belt tensioner are operating properly.
• Manually cheque the belt tensioner for proper performance. Make sure the tensioner pulley turns freely and without racket. Bank check it for damage.
• Manually plow the alternator pulley and brand sure information technology turns without a problem. If one of the bearings has seized, it won't let the alternator to turn freely.
• Check that the connections at the battery, alternator, and remote voltage regulator are clean and tight.
• Check for a diddled fuse or fusible link. Consult your vehicle repair manual, if necessary, to locate the alternator fuse or fusible link.
• Do the tests described in the department "Troubleshooting for Unusual Charging Organization Voltage Drops" beneath.

4. If the Engine Makes Noises

Noise tin can exist a sign of alternator bug when it comes from the charging system. The side by side checkpoints will assistance you lot isolate the source of the dissonance.

• Check the bulldoze chugalug or serpentine belt. Await for signs of wear or damage similar cuts, shiny spots or missing chunks under the belt. A worn out belt can squeal during operation.
• Also, check the belt tensioner for proper operation and damage. It should rotate freely.
• Brand sure the alternator is properly mounted. Loose mounting bolts tin cause the alternator drive belt and bulldoze pulley to become misaligned and noisy.
• Bank check the alternator for noises. Run across the General Charging System Checks section for a elementary procedure for this.

five. If Lights Dim During Engine Performance

Most alternators utilise diodes inside a rectifier to turn Alternating Current (Ac) into Direct Current (DC) for utilise by the system. When ane or more diodes go bad, AC tin can leak into the electrical organisation. Sometimes you tin notice this when the headlights, instrument panel lights, and other interior lights dim during engine operation. To test your alternator for Air conditioning current leaks, come across the Alternator Ac Voltage Leak Bank check subsection in the previous section.

Measure out system voltage and drop voltages using a digital multimeter.

Photo courtesy of Steve C on Wikimedia

Iv. Troubleshooting for Unusual Charging System Voltage Drops

A charging system voltage drop check tin can assistance you locate the source of an nether-charge or over-charge status due to problems in the wiring or connections betwixt the bombardment and alternator.

1. Commencement the engine and let it idle. Apply the parking restriction and set the transmission to Neutral (transmission transmission) or Park (automatic manual).

2. Turn on the high beams to provide a system load. And have an assistant raise engine speed to well-nigh 1500 RPM. If your vehicle is equipped with a heated windshield, don't turn it on; this tin make alternator voltage become over 100 V. Since you'll be working around alternator connections, this could be dangerous.

3. With your voltmeter test leads, touch the positive battery post and the B+ terminal connector at the back of the alternator.

four. Bank check your meter display. Y'all should get around 0.4V or less of voltage drop. If your voltage drop is higher, it can lead to an under-charge condition. Cheque the connections in that part of the circuit for a loose wire, corrosion at the connectors or wiring damage that may foreclose proper current flow betwixt the battery and alternator. As well, bank check the electric connections at the back of the alternator and at the voltage regulator.

5. At present echo the exam, but this time, connect your meter leads between the battery negative post and the alternator case.

half dozen. Check your meter display. Again, you should get a voltage reading around 0.2V or less. If your voltage drop is higher, there'due south something incorrect. This can atomic number 82 to an over-charging condition. Checking that part of the excursion, make sure the battery ground connectedness is good, clean and tight. Add a temporary footing connectedness from the battery to the chassis. If this removes the loftier voltage drib, check the engine to trunk grounds connections. They should exist clean, tight and in good condition.

Spotter the next video for a visual reference on voltage driblet checks.

Alternator problems are non uncommon subsequently a few years of operation. A typical alternator may concluding anywhere from viii to 12 years. So don't be surprised to detect your alternator going bad or the system developing problems after a few years of trouble-gratuitous operation, even if y'all have maintained your motorcar well.

The central point here is to do the proper diagnostic as presently as possible because a bad alternator can ruin an otherwise skillful battery, and other components as well, depending on the error.

One time you determine that your alternator is bad, you take several options. You tin supersede it with an original one from your dealer, an aftermarket replacement, or a rebuilt unit of measurement. Aftermarket alternators are a good selection and less expensive, and many of them are just as good equally their OEM counterparts. And rebuilt alternators are not as bad either. So consider your options.

This content is authentic and true to the best of the author's knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Questions & Answers

Question: I accept a 2012 Honda Civic LX, and I take put three new remained alternators in the last month. My lights would start to fluctuate, so I went in and had the store test it, and it would show a failure on the voltage regulator. But when I plow on the headlights, it would pass everything. Is there something else that could be causing this failure?

Answer: I don't have the manual for this model with me, but I believe the ECM controls the output. There could be a error in either the control circuit, i of the sensors the ECM uses to compute the output, or the ECM itself.

Question: I accept a 1961 Corvette. I changed the generator too a one wire alternator. Why do the diodes keep bravado out of them; significant five different alternators, under warranty. What's happening?

Reply: Make certain y'all got the correct unit for your application. Excessive heat is unremarkably the crusade for faulty diodes. Make sure alternator has adequate air period (for example, AC condenser or radiator clogged with bugs and dirt), engine heat shield (if whatsoever) in place. Another source of heat could be as well much resistance in the charging excursion. Check voltage drops on the charging arrangement and engine grounds equally well. These other two posts may help y'all:

https://axleaddict.com/machine-repair/Charging-Arrangement...

https://axleaddict.com/auto-repair/Automotive-Volt...

Question: I replaced the original alternator on my 2015 Kia Forte. The replacement alternator shows that information technology went bad and that I replaced it with the second one, now it went downwards. What is the problem? I accept also noticed the positive bombardment mail on my bombardment gets hot. Do you have any idea what it could be?

Answer: At that place could be too much resistance on that side of the circuit. Check the cable for impairment, or a trouble at the connectors. If everything seems okay, have your battery tested.

Question: I have a 2006 Volvo XC90 where the alternator commencement quit working, and so started working again. The battery light came on, and it started running off the battery. I brought it to the shop, and the alternator started working again. They couldn't get information technology to kick off over again, and then we left it. A week after the alternator went out again and stayed out. I just put a new alternator in and the battery is still not beingness charged; the battery light remains on. Any ideas of what my problem could exist?

Reply: Bank check the charging circuit, y'all may need the diagram for your particular model. Besides, make sure all the engine grounds are tight and free of corrosion.

Question: I accept an 03 Dakota. It needed a new battery, nonetheless, the battery gauge goes to 0, and the idiot light comes on after I bulldoze it for a minute. It starts fine and the lights are fine; just that approximate quits working. What causes that?

Answer: Check the alternator, peradventure a bad voltage regulator.

Brand sure the drive belt is non loose or the idler bad, causing the belt to skid. If the battery charge is not afflicted and everything else seems to work but fine, there could exist a loose wire or connector in the excursion to the estimate.

Question: I take a 1990 Ford F-150 and the alternator stays hot and won't charge the bombardment, any suggestions on what is incorrect?

Reply: First, make sure the chugalug is properly installed, not slipping, and accessory pulleys are running OK. Check the charging system wires for loose or corroded connections or damaged wires. This other mail service may aid here:

https://axleaddict.com/auto-repair/Charging-System...

If necessary, have the alternator checked (worn, bad voltage regulator) and battery. Hope this helps.

Question: What would crusade a charging organization to have a good amperage and voltage output at the alternator terminal and not see the amperage at the battery? I take done voltage drib tests on the cables and tried with new besides; the amperage is being fed to the cabin circuits.

Answer: Try connecting the meter in series between the ground side of the circuit - black probe to bombardment ground and cherry-red probe to the ground side of the excursion (car's torso) using the battery wire that goes from battery to the body. You should be able to read the amperage.

Question: I have a 1999 Honda Accord when I want to turn the engine on, the lights turn on, but when I switch the key to the cease, the lights turn off immediately, and the bombardment dies. I checked the alternator and the battery. Both work very well, only I don't know why the battery immediately dies after switching the key. What exercise you remember near this problem?

Answer: Seems like a battery trouble. Information technology doesn't take the amperage to outset the car. Accept the battery load tested.

Question: When I touch the alternator, information technology's hot enough to burn my paw, and information technology was merely running for a minute or 2. Why is that?

Answer: Peradventure excess of power going through the stator and rotor. This could be an internal alternator problem or a bad electric ground. Check voltage drops for the alternator circuits, particularly the ground side. These posts might help:

https://axleaddict.com/automobile-repair/Automotive-Volt...

https://hubpages.com/car-repair/How-to-Use-Voltag...

Question: I accept a 2002 Ford Mustang with a iii.8L engine. I was wondering if in that location is a fuse that could be blown to make it not charge?

Respond: Check the power distribution box, there should exist a fuse that connects to alternator power and a fusible link. The box lid may help yous find the fuse. If the alternator is not charging, check the belt's tension and pulleys, the connections between the alternator and battery, besides as the battery itself and alternator. Checking the circuit's voltage drib may assistance you test the connections. For this, go over this post, then you have an idea how to do information technology:

https://axleaddict.com/auto-repair/Automotive-Volt...

Basically examination between the alternator power mail service and battery power; then footing and battery footing.

Question: Volition there be any signs in a Chrysler car battery terminal, if you remove the terminal that at that place is a problem with the alternator and charging organisation?

Respond: If the alternator is overcharging, in that location could exist signs of corrosion; but the concluding may exist cracked or loose. Simply you may detect bug while the engine is running, but don't remove any connections while the engine is running. It tin touch on sensitive electronics. If y'all are trying to find a fault in the charging circuit connections, information technology'southward better to practice a voltage drop test. This will tell you the status of the connections. These other ii posts may assist you locate this type of issues with the charging system and engine grounds:

https://axleaddict.com/automobile-repair/Automotive-Volt...

https://axleaddict.com/machine-repair/Charging-System...

Question: I take a '06 Chevy Cobalt that has been running fine up until two weeks ago when one morning time the car would non start. Long story curt, I had the alternator replaced. And now it is withal dying in one case in a while. Apparently, it'due south overcharging! And in that location is a short. How practise I discover the short?

Answer: The overcharging may come up from a bad voltage regulator in the alternator. You should get between 12 and 15 volts with the engine idling at 2500 rpm, headlights on and fan blower on high.

If yous think yous have a curt, this other mail may help:

https://axleaddict.com/machine-repair/How-to-find-a-C...

Question: I accept replaced the alternator considering the battery wasn't existence charged. Afterward the alter, the same thing was happening. The engine starts, the bombardment calorie-free on the dash goes off. If you lot remove the negative terminal while running the engine, it shuts off (I know information technology's not a good practice). What could other problems I can bank check for? I oasis't checked the wires for proper connections as yet.

Answer: There could be some high resistance in the charging excursion preventing the alternator from charging the bombardment: corroded cables or wiring, incorrect wires or cable size; bad crimped connectors or loose connections.

This video shows a simple voltage drop test on the charging system that may aid you see if in that location are circuit problems:

https://www.youtube.com/watch?v=_B0LjwQbUbg

Question: I accept a 2001 Mazda 626. I was having bug with the battery belongings a charge. I replaced the battery and alternator, only the battery yet won't concur a charge. I constantly accept to put information technology on charger to be able to drive anywhere close. What could exist causing the problem now?

Reply: There could be a parasitic drain on the battery

https://axleaddict.com/automobile-repair/machine-batterydrai...

Also, you may want to check voltage drops in the circuit, make sure connections are clean and tight

https://axleaddict.com/car-repair/Automotive-Volt...

Question: When doing a battery test on my BMW 323i, the battery number on the left goes up above 14, then downwardly below 11, and the battery lite comes on. What could exist the problem?

Respond: Have the alternator checked. At that place could be a problem with the voltage regulator. Besides, if necessary, practise a voltage driblet test on the charging circuit. This other post may help:

https://axleaddict.com/automobile-repair/Automotive-Volt...

Question: I have a 2001 Toyota Solara with 158,000 miles. I've gone through 5 alternators in well-nigh 6 yrs. Fifty-fifty the Toyota oem. Two reliable mechanics can't figure it out. I'm taking it to a shop that specializes in electrical bug. Do you take whatsoever ideas?

Respond: Knowing how the previous alternators failed tin give a clue about the type of event you are dealing with (electrical, mechanical). Normally when alternators failed prematurely is because of a bad battery (electrical), voltage regulator bug, high electrical loads (e.yard. running Ac fan at loftier) or a drive belt that is putting unusual stress on the alternator pulley (mechanical)(make sure the belt is non besides tight). Alternator quality tin can be another factor of course.

Check for signs of fluid leakage around the alternator that might affect the stator or rotor or both.

Question: I have a skilful alternator, but my bombardment runs down. Information technology passed tests performed at two auto parts stores. When this problem occurred, I was able to get dwelling house by starting the vehicle (2000 GMC Yukon, 5.3L) past disconnecting the battery. Voltage when up shut to 14 according to the gauge. When I reconnected the batter at home, it was still expressionless. Got a new battery and have the same problem with battery drain. Do you accept any ideas?

Answer: If y'all accept some power amplifier, or some other power accessories, this could be running down the bombardment if the alternator tin can't keep upwards with the demand. Other than that, you may want to have the alternator checked in a shop, and see where the charge is going while the engine is running.

Y'all can check for a parasitic drain that you may not exist enlightened of. This post can help you:

https://axleaddict.com/machine-repair/motorcar-batterydrai...

Question: I installed a new 105-amp alternator in my 1982 Chevrolet C10. When I starting time the engine, information technology indicates 14.6 volts on the voltmeter connected to the battery. When I start the AC fan and the AC compressor, the voltage increases to 15.8 volts. After a while, the alternator stops charging; I retrieve it might exist defective. I changed two alternators, simply I still take the same problem. What do you lot think?

Reply: Check the voltage regulator and the battery. An motorcar parts shop may cheque the bombardment for yous. Too, may certain the circuit connections for the charging system are clean and tight and check the engine trunk grounds.

Question: I accept a 2004 Taurus, and I've changed the battery and alternator simply the charging system light is still on. Any ideas why?

Reply: Check the fusible link, you lot can examination it with your multimeter.

Question: I got a 2012 Nissan Xterra. I only installed a new alternator and new battery. It starts up good and idles expert now too, merely when I give it total throttle and get shut to three,000 RPMs, my bombardment light and park brake lights comes on and flashes at me. And the bombardment volt gauge goes down a whole lot. What could be the problem?

Reply: Bank check the alternator belt and tensioner. Belt should take the proper pressure. If it's loose, it won't charge properly during difficult accelerations. Check voltage at the bombardment when accelerating (at idle and emergency brakes applied). You should get around xiii.v or and so. Otherwise, in that location could be a problem with the voltage regulator. You may demand to replace the alternator. If not, check the wires and connections between the battery and alternator.

Question: I have a 2005 Ford Taurus 1 mean solar day it wouldn't start. It finally started and flashing lights to check the brake system in the charging system, simply so it wouldn't start one time information technology was jumped. It kept stalling, and so we had information technology checked at an car parts shop. They agreed alternator replaced the alternator and it is still doing the same thing practice you have whatsoever idea what else could be wrong?

Answer: Check all the grounds -- battery to body and body to engine. They should be make clean and tight. Bad grounds can eventually, harm the alternator. Test for voltage drop on the grounds, bombardment and charging system.

Question: I had my alternator rebuilt. Now I am having a trouble getting it to accuse at idle, I get 14.five volts at 1500 rpm, just every bit soon as I release the throttle it drops down to bombardment voltage, I've returned the alternator one time already. He checked it once again, replaced the regulator and said it's putting out full voltage, but on the automobile, it'southward doing exactly as I mentioned earlier, no voltage at idle, full voltage when revving the engine. Could this exist a PCM consequence?

Answer: Bank check the chugalug and chugalug tensioner for the correct tension. Take a expect at the connections at the dorsum of the alternator, especially the B+ connector. On early models the indicator lite on the dashboard should come on when the ignition key is in the On position, otherwise, you'll have problems at idle. There could also be a problem in the charging excursion, a loose, corroded or damaged wire tin can also forestall full voltage at low rpm. Take a await at the grounds and the output wiring to the battery. Y'all may need the diagram for this. These other posts may help:

https://axleaddict.com/auto-repair/Automotive-Volt...

https://axleaddict.com/auto-repair/Charging-System...

Question: Bombardment tested fine, but alternator voltage would get up and down. Occasionally, a BATTERY SYSTEM FAILURE lite volition come on. Could it be a sensor/fuse problem since it doesn't stay on all the time?

Answer: The alternator could be faulty. But y'all may want to run a voltage drop test on the circuit outset. Some models, like GM, take a fusible link in the circuit. Make sure that information technology's skilful. This other mail service has a voltage drop department that may assistance:

https://hubpages.com/auto-repair/Charging-System-C...

Question: My voltage is fine when I start the vehicle, but after driving around for about 10-xv minutes, my voltage goes from 14v to xv.5-16v. I have an aftermarket voltage regulator, and a high output 320 amp alternator and my battery dies if I don't unhook the wire from my battery to the cars fuse box. Do you have any ideas?

Answer: You need to brand sure the alternator is suited for your application. These alternators need the right caster ratio and pulley diameter to work correctly. Besides check that it has the right size battery cables hook to the battery.

Question: Our engine will take too much time to kickoff. How tin can I check the alternator?

Respond: The trouble might be with the battery, starting arrangement, ignition or fuel arrangement. Bank check the concoction status, check for spark and fuel pressure.

Question: I have a Toyota Corolla VVTI model 2004, I have changed the alternator but the battery indicator is however present. I accept checked the fuses and connections, but the problem continues. What could be the effect?

Answer: Have the battery tested, and bank check the connections in the charging system. Make sure they're make clean and tight. Also, the cheque the engine grounds.

Question: What are the nigh common faults probable to occur in a charging organization? More than six points at least.

Respond: There tin be a problem with the circuit, voltage regulator, ignition switch, corroded battery cables, faulty battery, worn or loose drive belt, bad motorcar computer.

Question: I put my OBDll reader on my car and information technology says my charging arrangement output is high. What does that mean exactly?

Answer: This basically means the alternator is overcharging the battery. Unremarkably the trouble here is the voltage regulator. Earlier replacing the alternator, yous tin have the alternator to a local automobile parts store and have them check it for you. Make certain the alternator is the problem.

Question: I have a 2003 VW Eurovan. Recently, the ABS light went on, then, after a few minutes the regular red brake light lit and the motorcar stopped. What is going on?

Answer: You need to download the problem codes. There could be a number of things that triggered the ABS light - problems with the tone ring, wheel bearing, speed sensor (and wiring).

Question: I have a 06 Mustang GT. I replaced the alternator because it was causing a camshaft position sensor code. Later on replacing it and checking my work, the battery light with a warning "check charging arrangement" comes on. It comes on for a infinitesimal or then so goes out for a few minutes. The battery seems to stay around 13.7 volts what could be causing the light to come on randomly? I accept not driven it yet.

Respond: Check the circuit connections. This could exist a loose or bad wire/connector. You may want to endeavor a voltage driblet test. This post gives you an idea of the test:

https://hubpages.com/car-repair/Automotive-Voltag...

Question: I take a 2014 Nissan Pathfinder. I inverse my alternator in July 2018. Alternator stopped working once more on 2/half dozen/2019 and replaced it on 2/7/2019. Dorsum in the shop on ii/xi/2019 with bad alternator again. This time the alternator is overcharging. The alternators were bought from O'Reilly'due south motorcar parts. Just constitute out they are rebuilt alternators, and non new. Still, the cost was $400 for the office. Could there exist something causing the part to go bad and so quick or could information technology just happen to be bad parts?

Respond: Make sure you are using the correct battery for your awarding. On some newer models using the incorrect bombardment tin can bear upon the alternator, especially those that interact with the ECU. Also, check the belt and pulleys. Make sure the pulleys are correctly aligned, and the alternator is properly mounted without rust accumulation, especially the ground connections, including engine and battery grounds. Too, check the wiring for signs of electrical faults. And yeah, some models are very sensitive to using parts other than OEM, merely first, brand the previous checks.

Question: I accept a 1998 Ford Mustang. I've changed the battery and the alternator. I'm yet losing voltage from the alternator to the battery. Information technology is only running on the battery. What can cause this problem?

Reply: You might want to make a voltage driblet test on the charging circuit. There could be a bad connection or wire that is not too evident. This other post will give you lot an idea on how to go virtually the test:

https://axleaddict.com/auto-repair/Automotive-Volt...

Question: I accept an 04 Lincoln aviator. I changed the battery, alternator and I am nonetheless getting a bank check charging system bulletin. What do I do side by side?

Answer: Brand sure y'all actually have a charging problem. Your local machine parts store can check the alternator and bombardment for you lot. If in that location's a problem, information technology could be in the excursion. If non, the circuit for the warning light might be the result.

Question: What causes voltage to fluctuate?

Respond: There could exist several causes backside the consequence:

bad alternator, bad voltage regulator, bad connections between the bombardment and alternator.

Starting time, make sure the connections are clean and tight, and the cables are practiced. Specially, check the grounds betwixt the engine and body. Then, accept the alternator tested in your local auto parts store.

Question: What would cause my alternator to exist charging where it supposed to exist, so cause it to drop all of the sudden? You lot tin can barely tap it and it goes dorsum up.

Answer: Probably you are dealing with an alternator with worn brushes. Borer the alternator milk shake the brushes a fleck and help them make meliorate contact or the copper wires continued to the brushes are damaged.

Question: I have a 1966 Ford Mustang and accept swapped out the alternator 3 times. It will work fine at times, then at other times the voltage steadily drops, especially if I turn the lights on. The belt is good, connections are good. The bombardment is good. Any ideas equally to what the trouble could be?

Answer: Make sure yous take clean and tight connections to the voltage regulator. If necessary, have the regulator checked. it might not be sensing the voltage driblet at the alternator when load increases. And the battery doesn't get the required accuse. Promise this helps.

Question: On my mode home, the alternator light came on simply made it home fine. The next solar day, the truck was hard to crank and would only stay running if my foot remained on the gas. The next solar day, I charged the battery and put it back in. Idea it was fixed but now the battery is dead and won't recharge. What's the problem at present?

Reply: Accept the battery and alternator checked. If the alternator or charging organization was faulty, it could've damaged the battery. Also checking the charging system voltage driblet may aid in the diagnosis.

https://axleaddict.com/auto-repair/Charging-Arrangement...

Question: I have a 2012 Town and Country with 110k miles. Terminal twelvemonth at around a 100k miles I replaced the alternator due to regulator failure. This twelvemonth I installed a new battery. The problem is the charging light comes on randomly. I drive effectually with a voltmeter to run these tests the moment it happens, but everything checks out. Why does the light come on and not go out?

Answer: Check the chugalug. A worn chugalug may slip intermittently, affecting the charging system. The trouble with newer belts is they look good even if they are worn. Check the chugalug for tension and wearable (utilise a belt clothing guess), tensioner, pulleys, and grounds, and especially engine grounds.

Question: I have a 2007 Cadillac CTS. I replaced the battery, cranked up and the negative connectedness got hot. What would cause my Cadillac's battery to oestrus up?

Reply: If the negative cable gets likewise hot but cranking the engine, there'southward also much resistance in that role of the circuit. If this happened right after installing the new battery, probably the negative cablevision is not well connected or is damaged or in that location's some corrosion. You tin also do a voltage drop exam on that role of the circuit. These posts may aid:

https://axleaddict.com/auto-repair/How-to-Use-Volt...

https://axleaddict.com/auto-repair/Automotive-Volt...

Question: I take a GM 3500 6.0 with an overcharging problem. I ran new wires to the PCM and fuse box for the connector. I have a brand new alternator, PCM, and ACDelco battery. The power wire for the alternator to the battery reads correctly likewise. But it is still charging to fifteen.6-16.0. What could possibly be going wrong with my car'south alternator?

Reply: The problem could exist on the basis side of the circuit. Increased resistance (loose, corroded grounds) can cause this type of problem. Of course, yous want to make sure you got the right alternator for your application. This other mail may help:

https://axleaddict.com/auto-repair/Charging-System...

Also, brand sure to lookout man this other video:

https://world wide web.youtube.com/watch?v=OqylgRKiC-A

Question: When my engine is at idle the voltage is effectually 13V, only when I plough on the headlights and AC, information technology drops to 11V to 11.8V. What seems to be the trouble?

Answer: My guess is the Ac pulley may exist putting a strain on the crankshaft caster, affecting alternator output. Or the AC caster is affecting the belt. Check how the iii operate when the Ac is on.

Question: I have a 2003 VW beetle. I take changed the alternator more than 8 times. I finally got the right one through the VW parts, but information technology's still non charging back my battery, and I bought the battery a yr and a one-half agone. I have been charging information technology and it still holding battery, so it's driving me crazy equally to why is not working. Can you help?

Reply: The problem could be in the circuit. If your detail model has a fuse (check your repair manual) information technology may be diddled. Less likely, simply it could happen, a fault in the computer can forestall the alternator from charging the battery.

Question: I take a 2011 Mazda 3, ii.5. The bombardment light turned on when I was driving at 120 km/h and would plow off if I slowed down. The light now starts at 90 km/h and volition turn off if I slow downwardly (possibly rpm related, non sure). Battery, alternator and start engine were tested at the dealership just seem to be OK. The battery seems to slowly drain within a few weeks as the speed decreases for the bombardment light to turn on. What could it be?

Respond: This may exist an alternator issue with worn brushes, slowly losing the ability to charge the battery. A common test is to replicate engine rpm at which the lite comes on. Lookout man the engine rpm when the battery light comes on. At home, with the transmission in Neutral or Park, increase engine speed to the same rpm and see if the low-cal comes on. If it does, the alternator needs new brushes.

Question: 2002 Mitsubishi Magna. Battery 12.43v, drops to xi.98v at idle. xi.95v from alternator. There seems to be no AC leakage. Fuses all good. Wiring seems all good. Voltage to alternator from battery is correct (connector tested). Is the alternator just producing low voltage considering the alternator is faulty? I should mention information technology is absolutely covered in oil from an oil leak; wiring is muddy only working. Could oil inside the alternator be the cause?

Respond: Oil can definitely impact the alternator. If you have fixed the oil leak, check the alternator circuit voltage drop to make certain it is not interfering with current. This other mail service may help:

https://axleaddict.com/auto-repair/Charging-System...

Question: I have a 2000 Civic EX 2 door coupe. The alternator went bad, and I replaced it along with the battery. The machine runs fine. It seems to charge the battery, but then the battery lite comes on. I have driven the motorcar, and I haven't had whatsoever problems running the AC, lights or radio. I can unplug the alternator, plug information technology back, and the light will go out. Simply as shortly as I plug it in, the low-cal comes on again. Doesn't seem to change the engine running or idle when I unplug the alternator. What could be the problem?

Respond: If there are any DTCs, clear them from the computer retentivity. Also, check the fusible links. Make sure they are still well connected and skillful.

Question: Bought a remanufactured alternator for my 2004 Civic today. I cannot go the wiring connector to snap back into the receptacle on the alternator. Can you give me some pointers, please?

Answer: Brand sure the harness clip or connector is non damaged or broken. If the connector is OK, make sure yous have the right alternator for your detail model.

Question: What would crusade a new alternator to whine and take the pulley oestrus up excessively? Starting at ambience air and shooting upward to 275+ degrees. But when the battery cables are disconnected while the engine is running, the alternator pulley runs shine and there is no excessive heat build upwardly. The battery is also brand new.

Answer: This is unremarkably acquired by a faulty diode(s), making alternator work extra-difficult. Cheque voltage output; also, check the accuse excursion voltage drop:

https://axleaddict.com/auto-repair/Charging-System...

Question: I have a '03 Chevy Silverado alternator that whines and displays a check engine code, mainly knock sensor. Occasionally cylinder seven and 8 are too lean. I suspect a bad ground. Do you know where I tin find a visual of where all the grounds are on this truck?

Respond: If you don't have the repair manual for your specific model, cheque your local public library. They may take the transmission in the reference section. Alternator whining sounds may come bad bearings, bushing or misaligned, worn belt, even a bad diode on some models.

Question: I have a new but inexpensive alternator. What could exist causing such a large fluctuation in voltage?

Answer: The diodes could be leaking or shorted. Have the alternator checked before replacing it.

Question: I take a 2004 Chevy truck and the gauge will stay at fourteen volts but sometimes it'll drop down to 12 volts. Is this normal?

Answer: Check for a loose connection, wire or cable betwixt the battery and the alternator. Wiggle the wires and see if the voltage changes. Also have the alternator checked, if necessary.

© 2017 Dan Ferrell

hallertrong1980.blogspot.com

Source: https://axleaddict.com/auto-repair/Alternator-Problems-Troubleshooting

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