Ford F-150 battery light comes on and off

Why My Ford F-150 battery light comes on and off?

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The Ford F-150 pickup truck is one of the best-selling vehicles in the U.S. It has some special features and user-friendly quality so many people like to buy it and use it for their needs.

But today’s topic is not about the details of this vehicle. Today I want to discuss the causes and diagnosis of the Ford F-150 battery light that comes on and off.

If you see that, your Ford F150’s battery light is on, it indicates a few issues.  When you see that, your light is on, it means there is some problem with your charging system.

The charging system of this vehicle is simple. But sometimes it may be caused by a bad battery or alternator.

We all know that a battery needs some voltage to start the vehicle. When the battery voltage is too low to start the vehicle, it can be detected by seeing the battery light turn on.

If it happens, the battery lights will come on when you start the car. If your battery is old, you can see these things mostly in the winter season. And that’s why you will face difficulty to start the vehicle.

After starting the vehicle, if you see your battery light is on you may think your battery is damaged. But it is not the only reason for the light being on.

Battery damage is one reason but not the only reason for it. So you need to know the factor perfectly. 

Let’s now solve the Ford F-150 battery light that comes on and off. 

The most common reasons battery light comes on and off

Most common reasons battery light comes on and off

Here I am describing the reason for battery light-  

1. Battery (Primary reason)

The battery is necessary for starting any vehicle. When the vehicle starts it can run off the alternator. It is an important factor to know. You can recognize a bad battery when you start the vehicle.

However, you may need to replace the battery with a new one. You can choose a new battery from Amazon.     

check our detailed guide about the best battery for a car

Our recommended best Ford F-150 Battery:

Optima-Batteries-8003-151-Starting Battery

Optima-Batteries-8014-045-YellowTop-Purpose Battery

2. Alternator

You can recognize a bad alternator when the engine is already running. When you see your battery light turned on while the engine is running, it warns you that the alternator of your vehicle has less capability to produce wattage for various electrical systems and charge the battery at the same time according to its demand.

To solve this problem, you need a new alternator. You can choose from the below options!   

Our recommended best Ford F-150 Battery Alternator:

Alternator-AFD0110-Output F-150-Pickup 


3. Alternator Belt

For the purpose of turning the alternator, almost all modern vehicles use a serpentine belt. It has the ability to turn the alternator more powerfully than one engine accessory.

If the serpentine belt is damaged, your Ford F-150 pickup will be unable to get an adequate charge as the belt has lost its ability to turn the alternator accordingly.

4. Battery Post Corrosion

The vehicle needs energy. This energy comes from the voltage of the alternator. So, the vehicle needs to pass the voltage from the alternator to the battery.

These voltages pass the path through a wire which is connected to the battery post. If the battery post is corroded, it will be unable to pass these voltages from the alternator to the battery according to its demand.

When it happens, the battery light will turn on which indicates a problem with it. But this problem is not very difficult. You can solve it easily. Just you need a battery post cleaner or wire brush to clean it.

But in doing this work, you need to be careful about the corrosion not getting in your eyes.

You may read also why my projector keeps cutting out

How to Diagnose Ford F-150 battery light comes on and off

Diagnosis of low-performance cooling system of the hybrid battery

When you see that your battery light is on, you need to test two things. Voltage and battery. For testing these, you need a digital multimeter

You might be interested in the thermostat backlight not working

1. Voltage Test

For checking whether your alternator is working or not, you need to use the multimeter properly. The step of using the multimeter is given below.

– For reading the voltage you need to set the millimeter. Actually, the voltage of the multimeter should be 20V DC.

– After turning off your F-150, you need to connect the multimeter.

So, connect the negative side of the tester to the negative battery post or negative wire and the positive side of the millimeter to the positive battery post or negative wire.

Now, get a reading somewhere between 12.0 volts and 12.6 volts when the engine is off.                                                                  

– Now we will look up at the third step. We will turn on the engine and keep off the air conditioner as well as headlights and all other accessories.

– Then, look at the voltage level. You can see the voltage is over 14.2 volts. If you find your voltage over 14.2 volts, it indicates that your engine has no problem so you need to replace your alternator.

But if the voltage is under 12 volts, you must have to replace the alternator.

If you find that your voltage is 13 volts, then it’s time to take the vehicle to the part store and test it. Maybe the alternator has some problem that needs to be solved.

– After confirming your voltage level over 14 volts, it’s time to repeat the process to all other possible parts of your vehicle. The possible parts are headlights, air conditioners, radios, and many other accessories.

You need to connect the negative and positive sides of the millimeter to the negative and positive battery post or wire respectively. After that, check the voltage in the same way as the previous one.

If the voltage is over 14.2 volts, there is no problem and if it is 12 volts, you need to replace the part. 

2. Battery Test

If there is no problem with the alternator, it’s time to check the battery itself. I want to recommend you to take the battery to a local part store.

They will check it and tell you whether it needs to be replaced or if they can fix the problem. 

Ford f-150 battery terminal connectors you may need to use:




Ford F-150 battery light is a strong indicator for the problem of your alternator or battery. So if you see the light is on, you have to check your battery or alternator and reinstall the part or fix the problem as early as possible to enjoy a safe journey.

This is how the Ford F-150 battery light comes on and off. 

And, if you love any of our recommended products, then please feel free to order and buy on Amazon. We always try to recommend the best product for your particular requirement.

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