What to do if Battery Warning Light comes on Intermittently

If your battery light flashes on now and then, then you may have a bad alternator, fuse, or a wire is loose.

Your car is designed to give signals that can alert you on some issues of its system. For example, while driving, you may see the battery warning light turning off and off intermittently.

Do not panic or think your vehicle has become damaged; only a battery warning light is there to alert you that the voltage supply for the battery is not in order.

Several indications could result from a battery warning light, such as the alternator failures. The alternator’s function is to produce a voltage that fills up the battery for the vehicle locomotion.


Why Battery warning light comes on intermittently

Whenever a car starts, it is normal for the battery warning light to turn on briefly then back after some seconds. This system test shows that the battery light on the dash, alongside any controlled components of the charging system, is functioning as required. A battery’s warning light will stay on if a fault is detected in the charging system. If this happens, there are several potential reasons to check out when troubleshooting.

Bad Alternator

When the battery warning light comes on intermittently, one thing you can suspect is the alternator being bad. Of course, the alternator can affect the voltage supply for the battery. You have to know that alternator is responsible for charging your vehicle’s battery. Some conditions can lead to alternator damage, such as water drops or splashes. This means when driving your car in a flood area or immersing the vehicle deep in water is a risk to the alternator.

Most parts of the alternator can be damaged, such as its electronic connections and brushes. Water can also affect shaft bearings and also cause corrosion. If the corrosion continues for a long time, the wiring inside the alternator may stop functioning. When the alternator is damaged, you may see the battery warning light turning off and on intermittently. But how can you know it is an alternator bad causing the battery warning light to turn off intermittently?

How to test an alternator

Testing the condition of an alternator is simple, and you can test to know whether it is good or damaged. The best testing tool to use here is the multimeter. A good or standard alternator should have a voltage range between 13.6 v and 14.6 v. If you test the alternator and indicate a reading of voltage below 12v, the high chances are that the alternator is 100% damaged. What you should do next is to replace the alternator with a new one.

A bad fuse

A bad fuse can cause a battery warning light to come on. A broken fuse on the charging system can be a reason for battery lights. A car battery charging system has a safety fuse used to connect the battery to the alternator. When this fuse breaks or becomes faulty, the flow of the electric current will stop. The termination of the electric current from the alternator to the battery will make the lights come on.



How can I tell that your fuse is bad?

If your car’s fuse is faulty, it will have the following symptoms

Lose of power for the car accessories and functions. If some of the car’s accessories like radio, Wipers locks, or power windows suddenly stop functioning, the problem might be a faulty fuse

A blown fuse is a more direct sign of a defective fuse. The wire inside the fuse will be burnt or broken.

Loose fuses

Burned terminals

What to do if you have a bad fuse

After you have determined that your fuse is bad, you need to fix it.


How to fix a bad fuse

Unplug electrical appliances

Turn the power off

Find the fuse box

Identify the broken fuse

Replace the fuse and test the new setup.

If your fuse is constantly falling, it is a sign that it has a more complicated electric issue. And in this case, you can take your car to a mechanic for assistance.

Bad battery

A bad battery can be a potential cause for the occasional battery warning light. A standard 12-volt battery can last for about three to five years. However, some manufacturers tout a longer lifespan, but such batteries should not be expected to last longer. Conventional batteries contain a lead dioxide plate plus a lead plate submerged in the sulphuric acid electrolyte solution in the six cells.

As the batteries age, the plates or cells can break, leading to the leaking of the electrolyte solution. In addition to that, bad grounds or bad wiring can make the battery not hold or take charge.



How to test if the battery is bad

You can quickly tell that your car battery is bad if it shows some symptoms. These are the symptoms you are likely to see

Battery light illuminated on the dashboard


Engine cranks slowly when starting

Clicking when turning the engine


Car not starting

Dim lights



However, if you want to be sure that your battery is bad, use a multimeter to test the battery. Here are the steps for testing your battery with a multimeter

Step 1: Turn on headlights for two minutes.

Step 2: Set the multimeter to fifteen to twenty volts

Step 3: Turn off the lights

Step 4: Connect the multimeter to the positive and negative battery terminals

If the battery voltage is below 12.6 volts, your battery might be bad.

Step 5. Start your car and look for a revised voltage over ten

If the car voltage is below five while the vehicle is running, the battery is bad and needs to be replaced.


How to fix a bad battery

The only remedy for a faulty car battery is replacing it with a good one.

How long do alternators and batteries last

A battery’s role is to start a car while an alternator keeps the car running. Alternators tend to have a longer lifespan compared to batteries. According to most manufacturers, an alternator can last for about seven years or about one hundred thousand to one hundred and fifty miles. However, there are those mechanics that say that an alternator can typically last for eighty thousand miles.

This depends on how often you drive the vehicle model and the number of miles that the vehicle goes. On the other hand, a car battery can last for three years, but the lifespan will depend on the type of vehicle, climate, battery brand maintenance, and driving patterns.

If the battery warning light comes on intermittently, just know that it is communicating that there is something wrong with the side of the voltage. Therefore, it’s good to check up on the voltage system to find out whether it is alternator, battery or fuse bad.

Other causes include damaged alternator belts, corroded battery terminals or bad cables, ground straps, wiring faulting and an overloading charging system with many accessories.