Ford F150 Battery Light Comes On and Off

Why Do My Ford F150 Battery Light Comes On and Off [Causes & Solutions]

The Ford F150 truck is one of the most popular automobiles in the US, thanks to its many unique features and easy-to-use characteristics that make it an attractive option. This article, however, will not look at the specifics of the vehicle. Instead, we’ll discuss why the ford F150 battery light comes on and off, what it means, and how to take care of the problem. 

Generally, when your battery light comes on, it is a signal that something is wrong with the charging system. 

In this case, what is wrong? What do you do? Read on to find out. 

Why does my Ford F150 Battery light come on and off?

The charging system in automobiles hasn’t evolved much for decades – the alternator is turned by the engine, and the battery is charged. Because there isn’t much to it, finding the faults is pretty straightforward. If your battery light comes on after starting the vehicle, you might think the battery is faulty. However, this isn’t the only reason the light is turned on. It may be one of the following issues. 


The battery is the most important element required to start any vehicle. The alternator starts to run as soon as the car is turned on and it begins to charge the battery immediately. But if your battery is defective, it will be difficult for your F150 to start. Usually, this implies that the battery has reached the end of its useful life and is due for a replacement. 

The battery power is supplied primarily from the alternator’s voltage. This voltage is transferred to the battery terminals through cables. However, if the battery terminals are rusted, the energy transferred will be low and inadequate. 

When this happens and the battery does not receive sufficient voltage, the battery light comes on. Fortunately, this is not a critical problem and can be corrected with a brush and battery post cleaners. 

If you are cleaning the terminals yourself, ensure that you don’t allow the rust to enter your eyes. 


It is not difficult to tell if your alternator is defective. If the battery light is on when the engine of your Ford F150 is running, it implies that you have a failing alternator. This means that your alternator is unable to produce the power needed by your battery, as well as electricity to the other components. A new alternator is usually the solution to this problem. 

The error may also be from the alternator belt. Almost all vehicles today use a serpentine belt to turn the alternator because it is powerful and can turn more than one engine component. But if this belt goes bad, it will be unable to turn the alternator and generate any significant charge. 

How to detect your Ford F150 battery light problem

When your battery light turns on or off, it is a signal that either your battery or your alternator is faulty and to detect exactly the source of the problem, two tests can be carried out. These are the voltage test for the alternator and the battery test. 

The voltage test can be performed at home with either a voltmeter or a multimeter. Let’s take a look at how to go about the tests. 

Voltage Test

detect ford f150 battery light problems by voltage test
  • Adjust the settings of the multimeter voltage to 20V DC. This is because we expect to get a voltage in the 2V to 20V range from a battery which is a DC source. 
  • Turn off your engine and connect the negative side of the multimeter to the negative terminal of the battery. Then, connect the positive side of the battery to the positive side of the multimeter. If your engine is off, the voltage reading on the multimeter should be between 12.0 volts to 12.6 volts. 
  • You can now start the engine since a benchmark has been established. Turn on the engine but don’t switch on the headlights, air conditioner, or any other accessory. Measure the voltage reading on the multimeter. 
  • With the engine turned on, the voltage should increase to 14.2 volts or more. If you get this value, it means that your alternator is charging properly. If there is no change on the multimeter reading and the voltage is still close to 12 volts, it indicates that your alternator is bad and should be replaced. Finally, if the multimeter reads 13 volts, you should have it tested in an automobile parts store as there are chances that it’s bad. 
  • After confirming that the alternator is generating over 14 volts, it’s time to turn on the air conditioner, radio, headlights, and every other accessory to take the final readings. If there is a drop in the voltage from 14 to 12, there is a good chance that your alternator is faulty. In this case, you should get it tested with the expectation that you may have to replace it. 

Battery Test

The battery test is done when there is no problem with the alternator and it appears to be charging the battery properly. You have to visit your local store to test the battery. 

Most of the time, this test is carried out free of charge and if they discover that your battery is the problem, it will be replaced. 

How to reset the battery light on a Ford F150?

Battery problems do not always necessitate replacement because there may still be an issue to be rectified. 

You can analyze the battery by troubleshooting with the following steps:

  • Check for corrosion around the battery terminals, as this might cause issues with electrical conductivity. To check, carefully remove the battery cover and look for a greenish substance around the terminals. If this is present, it means a case of corrosion. 

Corrosion is a fairly common occurrence in automobiles that are used frequently. Touching the battery with your hands is not a good idea.

  • The presence of corrosion at the battery terminals may be the cause of the battery light turning on. To clean, you’ll need a brush, hot water, and some elbow grease. Switch off the engine and disconnect the wires by taking out the battery cover. Thereafter, apply the oil and gently scrub it with the brush. 
  • The battery light may turn on if there is a shaky connection between the battery and the cables. When inspecting the battery, make sure the clamps are securely fastened to the terminals. If the clamps appear to be a little loose, tighten them with a tool or pliers.
  • Check all components, such as the alternator and its belt, before resetting the battery. It should be the first step in the process. Your battery will die if you do not fix it before resetting it.

Resetting your battery light is the last step. To do this, you have to modify your vehicle’s computer system. This is done by first getting the diagnostic information, then disconnecting the battery. 

After disconnecting, visit the truck’s home page and use a data stream to charge the battery. Other battery settings such as voltage, charge, and temperature can also be customized.

Will It Be Safe If I Drive My F150 With The Battery Light On?

The battery light coming on is an indication of a problem with the vehicle’s battery or alternator. This is why it is advised not to drive when this is noticed. 

If the vehicle shuts down abruptly in the middle of the road, the battery will likely be without voltage and fail to start. 

If the battery light comes on after you start the vehicle, don’t drive it until you’ve had it checked. 

Sum Up 

The battery light on your Ford F-150 is a clear indication that your battery or alternator is malfunctioning. It is important to check these components if the light comes on. Doing that is the first step to correcting the problem as soon as possible. 

These checks and fixes may be the difference between having a safe and enjoyable journey and getting frustrated when your vehicle stops abruptly.

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