Charging System Failure? [Diagnose & Fix]

Are you used to charging your phone in the car while you drive to the office? If yes, you are not alone. From where does the electrical current come? The charging system produces the electricity in the car. So, you are set up for frustration if a charging system failure crops up one day. Without this device, the car battery would not have any charge.

charging system of the car

The charging system is an essential part of the car. Without it, you cannot even start driving. Therefore, today we are going to discuss how to deal with a charging system malfunction.

What Is The Charging System In A Car?

Now, a lot of systems on an automobile run on electrical power. Where do we get it? From the engine, of course. When the engine is running, the charging system fills up the battery with electrical energy. The electrical systems in the car, like the radio, lights and other features, then utilize it from there.

charging system components, battery, alternator, regulator/ECM

The modern charging system consists of the alternator, battery, wiring and the electronic control module (ECM). As you can see in the diagram, the constituent parts connect electronically to each other. The alternator converts the rotary motion of the engine to electrical power. A diode rectifier converts the alternating current to DC and transmits it to the battery.

How Do You Diagnose A Charging System Problem?

The first step to figuring out the complication is inspecting its components. Once the warning light for the check charging system” shows up on the dash, we should learn what leads to it.

What are the symptoms of a charging system failure? When any of the charging system components fail, you may experience a loss of power. The headlights will dim, and the cabin lights may turn off. Over time, other equipment powered by the battery will stop working. When the battery is out of charge, you can not start your car. And, of course, the warning light will be visible.

What Is A Charging System Light?

The charging system light appears when the electronic control module (ECM) detects an issue with the battery or the alternator. Unfortunately, there isn’t one particular answer to why the warning light comes on. There could be issues with the alternator, drive belt, battery, corrosion in the wires and connectors, or even a fault in the ECM itself.

the charging system light warns you of a charging system failure

In some cars, the battery symbol appears during driving in place of the above indicator.

Now, let us look at the parts that can develop a fault.

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1. Fuse

Is there a fuse for the charging system? Yes, indeed, there is one. The purpose of a fuse is to protect sensitive and expensive components of the car from a power surge. As such, pretty much every electrical system you see has a fuse. The location of the fuse box varies from car to car. To find the one for your automobile, consult the owner manual.

The primary alternator fuse (or fusible link) will burn out in case of enormous current flow through a short circuit or any other malfunction. With the electrical circuit now broken, the charging system will not function as it should—and you will start noticing an assortment of problems. First, we should check whether the fuse has indeed blown. For that, you will need a multimeter set to short circuit test mode.

Solving this issue is a simple task. Merely replace the fuse, and everything works again. However, keep in mind that fuses do not blow out on their own. The fault that caused the high current draw, probably a short in the wiring or corroded connectors, still needs repair.

2. Alternator

Typically, the alternator is behind the charging system failure. If it cannot maintain the charge on the battery when the engine is running, the check charging system light warns the driver of the issue. In that case, service is imperative, and the sooner, the better.

a new alternator

What are the signs of a bad alternator?

  1. Dim or overly bright lights.
  2. Dead battery.
  3. Slow or malfunctioning accessories.
  4. Trouble starting or frequent stalling.
  5. Growling or whining noises.
  6. The smell of burning rubber or wires.
  7. Battery warning light on the dash.

Can a faulty (bad) alternator destroy a new battery?

Yes, a defective alternator can damage a battery by overcharging it. On the other hand, an undercharging alternator may keep the battery at a deficient charge for a long time. It may weaken some of the battery’s cells. As a result, its capacity will decrease, and it will require replacement as well.

3. Battery

If the battery capacity is inadequate, you will also notice dimming headlights. It is pretty much the same symptoms as a faulty alternator.

To check the battery, watch the steps in the video. You will need a multimeter to check the voltage. The voltage should be greater than 12.6V with the engine off. It should be greater than 13.8V when the engine is running.

4. Wiring And Connections

The charging system utilizes wiring to transmit power. So, it is critical to keep the wiring in good working order. Frayed or damaged wiring is not uncommon in cases of a defect. It is usually an easy problem to fix.

frayed/damged wiring; charging system failure may be traced back here

Due to the outdoor conditions that cars face regularly, eventually, corrosion finds its way onto the connectors. Visually inspect the connectors and the wires leading out from the battery for any damage.

corroded terminals can lead to a charging system failure

5. Drive Belt

A serpentine belt attached to the engine crankshaft drives the alternator. If this belt were to snap, the alternator would no longer function. Hence, you would have a non-operational charging apparatus.

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driving belt and the systems it runs; a snapped driving belt can cause a charging system failure

If the belt has indeed broken or severely worn out, you can detect it by a visual inspection.

How To Fix A Charging System Failure

After identifying the faulty part, it is time to change it.

1. Charging System/Alternator Fuse

Changing the alternator fuse is a simple task. You can buy a new fuse at any automobile spares shop by showing them the old one. If your car’s fuse attaches by bolts, you will need a socket wrench of the correct size. On the other hand, for a snap-in fuse, you will need pointed nose pliers.

2. Changing The Alternator

Faults in some other components could have damaged the alternator. Be sure to address them as well. Otherwise, the new alternator will face the same fate as the old one. Once that is done, replacing the alternator is an easy job. You will need a multimeter to check the battery and a socket wrench of the correct size to dismount the alternator.

3. Battery Replacement

Most car batteries have a lifespan of 4 years. That is how long the warranty usually lasts. Changing the battery is as simple as pulling out the old one and putting the new battery in. The tools you need are work gloves, a socket and extension, and a wire brush. Furthermore, you may require some cleaning and anti-corrosive solution and a cloth for cleaning.

Be careful with the connectors and exercise caution in handling electrical components. Allow the engine to cool before you start working.

4. Wiring and Connectors

If you have found some damage to the wiring, it is time for some repairs. In case of mild to moderate fraying, you should warp the wire in fresh electrical tape. That should solve the problem. However, if there is heavy damage, disconnect the wire and take it to an automobile spares shop to buy a replacement. Reconnect the new wire identically to the old one.

For connectors with corrosion, use sandpaper to remove the rust. Then use WD-40 to wipe down the connector. That will restore the circuit. Watch the video under testing the battery for more advice on corrosion removal.

5. Drive Belt

If you need to change the drive belt because of damage, you will need a wrench of the appropriate size. Make sure that the belt aligns correctly in the groves of the pulley during installation. Otherwise, you will end up with further damage.

Can You Jumpstart A Car With A Bad Alternator?

Yes, you can technically jumpstart a vehicle with a bad alternator. Turn off all your car’s electrical accessories to conserve battery power until you can reach a mechanic. As you might guess, it is only a temporary solution. Remember, it is a bad idea to leave jumper cables connected between vehicles longer than necessary. It can damage sensitive electronics.


Following these steps, you can diagnose the issues behind the charging system failure. Once that is done, replacing the defective part or parts is virtually effortless.

Driving with an activated battery/check charging system light entails the danger of being stranded. If your vehicle has a declining battery, defective alternator or damaged wiring, it could stop working at any time. Make an appointment with your mechanic before your car puts you on the side of the road.

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