Why does the battery light stay on when the alternator is charging?

If your vehicle’s battery light stays on, even when the alternator is charging, it could indicate that the battery circuits or the alternator system are malfunctioning. This will lead to improper charging. Having the battery light turn on when you’re charging can sometimes happen. But the light should go off after some time.

How do I know if it’s the battery or the alternator?

Both of these car parts control your electrical system. However, your alternator charges your battery while your battery supplies power to your car. The failures of a battery are sudden, while failures of a failing alternator are slow. Always check your battery first, it can generally tell you which of these two is the culprit.

What should you do if your alternator warning light comes on?

However, it is still dangerous to continue driving for long distances or at high speeds as the battery will run out of juice and the car will be harder to stop without the assistance of the engine. If you are on the freeway and this light comes on, you should pull off the freeway and move to lower speed areas as soon as possible.

How to check battery and alternator in Mercedes?

The dreaded battery warning light always leaves us not knowing if its the battery, the alternator or both. Watch as I show you how to check the state of these components via the secret diagnostics menu built into your Mercedes vehicle. Haven’t Subscribed? What are you waiting on? Do it today. Loading…

How do I know if my battery or alternator is bad?

Signs of a bad alternator. If the above steps reveal that the battery is working, it’s time to take a closer look at the alternator. There are certain signs of a bad alternator to look for: While running the car, note the brightness of the interior lights. If the dashboard gradually dims, the alternator is likely at fault.

How do I know if it is the battery or the alternator?

Check the Alternator. Test the alternator to make sure that it can start up the battery. If the battery is working properly and nothing is wrong with it, then it’s the alternator that will more likely cause a problem. Try to start the engine and listen carefully, if it produces a “whining” sound, it may be the alternator.

How long does it take for the alternator to charge the battery?

You can charge a flat battery to 80 percent full in about 2 hours, so long as you alternator can manage produce around 14 volts at the battery terminals this whole time.

What causes an alternator to go bad?

Reasons an Alternator Would Go Bad Failing Diodes. An alternator is essentially composed of three smaller alternators that each supply varying levels of power. Defective Bearings. Alternators revolve on high-precision needle bearings that you generally cannot hear. Insufficient Field Voltage. An alternator must have a field voltage of 12 volts to produce electricity. Worn Belt.

How does the alternator keep the car running?

Average rating from 11,564 customers who received a Brake Pads Replacement. The alternator on your vehicle uses the rotational power of the engine to generate electricity and keep the car running. The alternator needs to maintain a certain voltage in order to keep the battery at sufficient charge while driving.

What causes the battery warning light to come on?

Keep in mind that issues with the battery can also cause the light to come on so if the battery is old, it should be tested as well. It is better that you have a certified technician inspect and test your charging system to diagnose the problem in order to minimize any chance of permanent damage to your car.

What does the battery light on the alternator mean?

This is the same connector that lets the on-board computer know if the alternator is charging or not, which is what the battery light actually means. You can use a volt meter to test what the battery is receiving by connecting it to the middle of the posts while the engine is running.

What should the resistance be for an alternator?

If all this checks out then I suspect you have a wiring issue. I would perform either a voltage drop or resistance measurement of each of the wires from the PCM to the alternator. Also, through the fusible link from the battery to the alternator. You should have less then a half ohm of resistance.

Why does my alternator light go off when I raise the RPM?

Then if this light is going off when you raise the RPM then that means by spinning the alternator faster to increase the output puts the voltage over the minimum spec to turn the light off. If all this checks out then I suspect you have a wiring issue.

Why is the battery light on on my 4.6L?

Broken wire coming off the alternator. It may not look broken but it could be broke inside the insulation. That was the story with my 4.6L. The battery light would come on and off, wiggled the single grey wire and it would turn the light on and off.

What causes the alternator warning light to flash?

An alternator that is on its way out may cause this warning light to flash when there is a high demand on the battery. You can always save yourself a lot of trouble by paying attention to warning signs like this and trying to conserve your car’s battery.

What does it mean when your car battery light comes on?

The alternator can sometimes make a whining sound a few times before it goes–that is when your car battery light comes on as a sign that it is now completely faulty and needs replacing. It is usually the accessory or serpentine belt that is built inside the alternator that makes that type of noise.

Is it normal for the battery light to come on then turn off?

Yes! It’s perfectly normal for your car’s battery light to come on then turn off after you start it. Thanks! What do I do if my car is saying it has a low battery? You may need to replace the battery or alternator.

What are signs of needing a new alternator?

Warning Light. Many automobiles have a battery or alternator warning light on the dashboard.
Load Test. Conducting a load test will indicate whether or not your alternator needs to be replaced.
Voltmeter Test. You can test your charging system with a voltmeter.
Other Signs.

Why is your new alternator not charging your battery?

The most common reason for an alternator not charging a battery is because of a bad alternator or battery . You can easily test the voltage by connecting a voltmeter to your battery while the engine is off.

Will a car with a bad alternator start with a new battery?

A bad alternator can prevent a car from starting because it did not charge the battery when the car was running. However, even if you have a dead battery because of the alternator, you can still jump-start the car using the following method.

Why is my alternator not charging the battery?

If the alternator is not charging the battery you will have a red “ALT” or “charge” sign on your dashboard. This means that your battery is no longer being supplemented for power by the alternator. You will need to recheck the wiring because the light could also be faulty. Nov 22 2019

What should I do if my Battery Light is not coming on?

Try putting a new light bulb in the gauge cluster. Like i said i know it sounds retarded but on some charging systems it requires a good bulb to complete the circuit and allow everything to work like it should. I’m not sure that our cars are that way but I have ran into that problem before on other cars and it blew my mind. Click to expand…

What to do if your Charger light goes out?

Step 1: Start the engine. After all of these steps have been taken, the engine needs to be started up again to see if the charging warning light is still on. If the light goes out after starting the engine, check the charging system for any other problems.

What does it mean when your car battery light is on?

The battery light or charging warning light, available on the dashboard of your car, indicates malfunctioning or poor charging of the battery. This light illuminates whenever the charging system does not charge the battery with a voltage above approximately 12.5 volts.

Why does my alternator not turn on the battery light?

That battery is likely at or near the end of it’s useful life. A weak battery or working charging circuit won’t turn on the battery light. Since you pretty much ruled out the alternator I would make sure to check your fuses. IIRC there are 2 fuses for the alternator (will check my diagram later).

What causes battery light to stay on while charging?

Alternator problems can cause your battery lights to stay on while charging. Some indications of these problems are dim headlights, ‘charge,’ and ‘alt’ indicators light up. The battery needs copious water to operate, hard or slow to crank the engine, and alternator noises.

Can a single wire alternator turn off the charge indicator?

Since a single wire alternator no longer requires the exciter (IE the brown wire supplied in our Classic Update and universal kits) feed responsible turning off an in-dash charge indicator light, many users find out their quick and easy alternator swap has removed some of the functionality from their car.

Where is the charging light on an old car?

Alot of time on this old cars the regulator goes bad.The charging light comes off the regulator. It’s the red&green wire. The regulator is located on thr driver side mounted on the inside of the radiator core support.It is easy to change out. Start the car, take off the positive battery cable.

How can I tell if my alternator or battery is OK?

As with most electrical issues, if you know the battery or alternator is OK (because you had it tested), then diagnosis comes down to tracing and testing for continuity from one portion of the circuit (s) involved to the next.

What causes the battery light to go out?

Click to expand… Many charging systems put the alternator energizer wire through the light bulb. When the alternator starts charging positive voltage is equal on both sides of the bulb filament and the light goes out.

How can I test my car battery relay?

Assuming all fuses are fine, you can test relays by swapping them with others of the same part number (many vehicles will have two or three of the same relay running various components) or by testing the relay itself via continuity and resistance methods. The following two tabs change content below.

How can I tell if my alternator is charging before I change the battery?

Just get a good new battery. You could confirm before and after replacing your alternator that it is in fact charging, by measuring voltage across battery posts while idling. Personally I think you would have been better off buying a $10 volt meter instead of that $10 AEM cold air induction intake.

The dreaded battery warning light always leaves us not knowing if its the battery, the alternator or both. Watch as I show you how to check the state of these components via the secret diagnostics menu built into your Mercedes vehicle. Haven’t Subscribed? What are you waiting on? Do it today. Loading…

How can I tell if my alternator has a blown fuse?

The easiest way to look at the alternator is to check voltage at the battery. See what DC volts is and check for A/C voltage at the battery (meaning alternator isn’t converting voltage properly). Also check the amperage as well. My guess is you have a blown fuse.

Why does the battery light stay on when the alternator is off?

The alternator is definitely charging the battery and does not drain overnight but the battery light continues to stay on. Before spending money to test the fusible links, please advise If the alternator will still charge the battery with a faulty or blown out fusible link? Thanks.

Why is the battery light not turning on?

A weak battery or working charging circuit won’t turn on the battery light. Since you pretty much ruled out the alternator I would make sure to check your fuses. IIRC there are 2 fuses for the alternator (will check my diagram later). If your fuse check comes back fine, you likely have either a cluster problem or wiring problem.

What happens when you change the battery in a car?

A relatively common “side-effect” of replacing a battery and/or alternator in a car is to have the voltage (battery) warning light come on. This is especially true in late-model vehicles with their more sophisticated internal diagnostic systems. There are usually two things…

Why does the alternator warning light come on at full brightness?

Yeah this is full on irrespective of engine speed. You mentioned a fuse in your OP, the warning light will come on at full brightness if the fuse that powers the Alternator warning light blows or the wiring somewhere between the fuse and the warning light goes open circuit or the fuse is ok but loses the supply to it.

Why does your battery light keep coming on?

There are a few different reasons why your vehicle’s battery light came on. It could be a problem with your alternator, which recharges your battery while your engine is running. It could also be a wiring issue such as a damaged or disconnected wire affecting your battery.

Why does the battery warning light stay on?

The warning light for the battery will stay on if a fault is detected in the charging system . If this occurs, there are a number of potential causes to check out when troubleshooting. Safety is important whenever working with electrical systems, so check your owner’s manual for general tips.

How does a Battery Charger Charger light work?

Your charging light bulb in the dash gets its power from the 10amp GAUGE fuse. The regulator in the alternator grounds that circuit as necessary to make the light come on. Was the battery light on dim before you installed the new alternator?

Why does the battery light come on after the alternator is replaced?

This would make the Battery Light come on. It is also possible that there is a problem with the fusible link or the alternator fuse for the charging system.

A weak battery or working charging circuit won’t turn on the battery light. Since you pretty much ruled out the alternator I would make sure to check your fuses. IIRC there are 2 fuses for the alternator (will check my diagram later). If your fuse check comes back fine, you likely have either a cluster problem or wiring problem.

A relatively common “side-effect” of replacing a battery and/or alternator in a car is to have the voltage (battery) warning light come on. This is especially true in late-model vehicles with their more sophisticated internal diagnostic systems. There are usually two things…

Your charging light bulb in the dash gets its power from the 10amp GAUGE fuse. The regulator in the alternator grounds that circuit as necessary to make the light come on. Was the battery light on dim before you installed the new alternator?

Is it safe to drive with the alternator warning light on?

Is it safe to drive with the alternator warning light on? When this light is illuminated, your car is still somewhat safe to drive as you will have enough battery power to run the engine.

What causes a battery warning light on the dashboard?

See how you can fix the battery warning light on dashboard with this five problem that you can look at. While the battery light might seem like there is a battery problem, but in fact there could be other numerous issue causing the battery light to activate. To see what is really wrong with the car see this video for things you can check.

Why does the battery warning light come on after replacing the alternator?

A relatively common “side-effect” of replacing a battery and/or alternator in a car is to have the voltage (battery) warning light come on. This is especially true in late-model vehicles with their more sophisticated internal diagnostic systems.

How does an IDJIT light work with an alternator?

The idjit light essentially goes from the alternator output to the battery positive. If all goes well, both terminals are at the same voltage potential and no current flows. If either the battery or alternator are not at the same level, there will be current flow through the light and it will illuminate.

Why is the alternator light dim at hiatal?

Usually when this is the case, the light will be very dim at hiatal and will get brighter as you rev the engine. To diagnose the problem, put the positive wire of your volt meter on the alternator output terminal and the negative wire of your volt meter on the battery plus terminal.

When does the alternator turn on the idiot light?

When the engine starts and gets up to a high enough rpm for the alternator to start putting out voltage, there is a diode inside that takes some of the output voltage and featured back to the terminal that goes to the idiot light.

How can I tell if I have an alternator problem?

To differentiate an alternator problem from the battery, you will need to use a voltmeter to check for voltage. First, turn off the engine and check the battery voltage. A fully charged battery should have a reading of 12.65 volts. Next, turn on the engine and recheck the voltage. You should have a reading of 13.5 to 14.5 volts.

What happens when the alternator of a car is dead?

The alternator and the car’s battery work hand in hand. A good battery should give you service for the next five years before its lifespan ends. If your battery is dead, then it will not give power to the car’s alternator. The alternator normally lasts longer than the battery.

If all this checks out then I suspect you have a wiring issue. I would perform either a voltage drop or resistance measurement of each of the wires from the PCM to the alternator. Also, through the fusible link from the battery to the alternator. You should have less then a half ohm of resistance.

If your vehicle’s battery light stays on, even when the alternator is charging, it could indicate that the battery circuits or the alternator system are malfunctioning. This will lead to improper charging. Having the battery light turn on when you’re charging can sometimes happen. But the light should go off after some time.

What should the charge voltage be on an alternator?

Turn on the high beams for 10 seconds and then turn them off. Measure battery voltage across the battery posts with your DMM. You should get between 12.4 and 12.6V. This means your battery is fully charged. If you get a reading below 12.4V, charge the battery before continuing. 5b. Measure the Charging System’s No-Load Voltage

As with most electrical issues, if you know the battery or alternator is OK (because you had it tested), then diagnosis comes down to tracing and testing for continuity from one portion of the circuit (s) involved to the next.

What happens when the diodes in an alternator go bad?

Alternators use diodes to rectify alternating current produced by the alternator into direct current. When one or more diodes go bad, the alternator can cause all kinds of problems. AC voltage leak can cause your lights to dim and drain power from your battery, for example.

Is the alternator at the heart of the charging system?

Dan Ferrell writes about do-it-yourself car maintenance and repair. He has certifications in automation and control technology. The alternator is at the heart of the charging system of your vehicle. Alternator problems and charging system problems can affect your vehicle in different ways.

Why is the battery light on but alternator is charging?

You Alternator Regulator controls the output via an internal ground inside of the Regulator. If you are actually charging at 15 volts sometimes and it goes on long enough it can ruin a good battery. Also you might do a temp swap a Battery from another Vehicle. Even newest Batteries can have internal defects. Thanks for the advice!

How can you tell if your alternator is a problem?

How to tell if the alternator is the problem. If the battery is working, it’s time to take a closer look at the alternator. There are certain signs of a bad alternator to look for: While running the car, take note of the interior lights and how bright these appear.

What does it mean when your alternator stops the car?

If you can’t get it to restart, this is a sign the alternator is doing its job of keeping the battery working while the motor is running, but the battery isn’t retaining the charge when the alternator has stopped. The car battery could be old. As batteries age, they become less able to retain a charge because the metal inside corrodes.

Can a negative battery test a bad alternator?

Some may recommend running the engine with the negative battery cable disconnected to test the alternator. However, this is not a good idea because it could damage the electrical system of your vehicle and cause greater problems. Fixing your battery or alternator can be an expensive repair.

What happens when there is no battery light?

The Alternator cut-in speed is increased if there is no warning light on when in the ignition position Is the warning light coming on as it should with ignition on and no engine running ? Charging light is battery backed.

Turn on the high beams for 10 seconds and then turn them off. Measure battery voltage across the battery posts with your DMM. You should get between 12.4 and 12.6V. This means your battery is fully charged. If you get a reading below 12.4V, charge the battery before continuing. 5b. Measure the Charging System’s No-Load Voltage

When do I need to change my alternator?

If you do not change it soon, you WILL need to change it before winter… Save yourself money, change it now, if you still have enough pocket change to do it. It is quite possible you wore out your old alternator. This new one might also be getting old, so it is best not to stress it.. I agree.

What does the charge indicator light mean on a car?

Indicator Light On Usually, the first sign that your charging system is in trouble is a “battery,” “ALT,” or “CHARGE” warning light 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 car is running on battery power.

What to do if both battery and alternator are good?

If both battery and alternator are good, then its either a wiring or ECU problem. Check the contacts on the battery terminals/connectors to make sure they’re not loose, dirty, or corroded. Then follow the ground wire (the black one) back to the chassis of the car to make sure it has a solid ground..

What does it mean when your alternator stops charging the battery?

Indicator Light On. Usually, the first sign that your charging system is in trouble is a “battery,” “ALT,” or “CHARGE” warning light illuminating on your instrument panel while driving. It means that for some reason, the alternator has stopped charging the battery and your car is running on battery power.

What happens when the check charging system light comes on?

What’s happening when the battery/check charging system light comes on? Whenever this light goes on, it means that the vehicle is running solely on battery power. If the problem continues and your charging system fails, the battery won’t be able to recharge and it will soon run down, leaving you with a dead battery.

Indicator Light On Usually, the first sign that your charging system is in trouble is a “battery,” “ALT,” or “CHARGE” warning light 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 car is running on battery power.

Why does AutoZone test the alternator and charging system?

Keep in mind, when you test your charging system while the car is running, or AutoZone does the same, the system voltage is being tested at the battery, and if it’s not getting a charge, the test cannot determine why. Either the alternator itself is at fault, or the wiring between it and the battery are.

Why is my car battery warning light on?

The most common causes of a battery light on are broken serpentine belt, faulty alternator, bad ground strap, faulty car battery or bad alternator wirings. Here is a more detailed list of the 8 most common causes of why your car battery warning light is on.

When does the battery warning light come on?

Discussion in ‘ 3rd Gen – 2007 – 2017 ‘ started by Zellerj, Aug 15, 2019 . Yesterday my battery warning light came on, and I pulled into an Autozone for analysis. The Autozone tech said the battery was good – passed a load test, and the alternator was supplying 14.2 volts to the battery under load and at idle.

What happens when the dashboard battery light comes on?

Your car can often run normally even if the dashboard battery light comes on because the car is capable of running off the energy that is already stored in its battery. The car, therefore, carries on running perfectly until its battery runs flat. After that, none of the car’s components will work.

Is there a problem with the alternator in Liberty?

Discussion in ‘ Liberty ‘ started by jonahb1987, Jul 10, 2019 . I recently had a breakdown. At first we thought it was the alternator, so I bought a new one. Had it installed at a mechanic and the same problem would happen. After being jumped, it would start but putter out in like 4 minutes.

How many watts does an alternator put out?

The majority of vehicles have a voltage regulator and an alternator that ensures the battery stays charged while supplying electricity to your vehicle as the engine runs. Usually, an alternator puts out around 500-1000 watts whenever necessary.

See how you can fix the battery warning light on dashboard with this five problem that you can look at. While the battery light might seem like there is a battery problem, but in fact there could be other numerous issue causing the battery light to activate. To see what is really wrong with the car see this video for things you can check.

Why is the battery light on but the alternator is charging?

1 Check for Corrosion. In some car models, the fumes from the regular functions lead to corrosion to collect on the battery terminals. 2 Clean the Car Battery Terminals. If you notice some corrosion or grime around the battery terminals, it might be the reason why the car battery light is still on. 3 Tighten the Battery Clamps.

Where is the alternator located on a car?

The alternator is located on the front of the engine and is driven by a belt. On some vehicles, this belt is easy to spot. On others, it can be nearly impossible without removing engine covers or accessing them from underneath the vehicle.

The majority of vehicles have a voltage regulator and an alternator that ensures the battery stays charged while supplying electricity to your vehicle as the engine runs. Usually, an alternator puts out around 500-1000 watts whenever necessary.

Why does the battery light stay on when the alternator is charging?