Skip to Content

Ford F150 Bad Alternator Symptoms

Ford F150 Bad Alternator Symptoms

Alternators are the charging component of the Ford F150 that supplies the electric current to various parts and lights. Moreover, these also charge the battery by converting mechanical energy into electric energy to run the engine and ignition systems.

Ford F150 bad alternator symptoms include brake lights won’t turn on, glitches in the computer system and sensors, flickering of lights, dead batteries, battery warning lights, and slow performance of electric components. Moreover, these also include hissing and rattling sounds, stalling issues, burning smells, and difficulty in starting the truck.

It is necessary to check the alternators first when any of the electric components in your truck becomes faulty. These are located under the hood of the vehicle and near the engine compartment. The alternators become bad early if your pickup is modern and equipped with many electric accessories that can overload them.

The brake lights won’t turn on

Brake lights are the electric components in the Ford tucks and are located on the rear side. Many times, these do not turn on when you press the pedal.

These are basically the safety lights to alert the other drivers that you are applying brakes so they can maintain the stopping distance and prevent collisions.

The brake light switch is on the side of the pedal, and it transfers the current through wires when you press the pedal.

These switches take power from the batteries, and they cannot supply power when they are not fully charged or dead because of bad alternators.

These lights can also blink when you press the pedal because of the low voltage supply.

Glitches in the Ford F150 computer system and sensors

You can see glitches in the computer systems of your Ford F150, and the sensors do not work perfectly. For example, you cannot play music, receive phone calls and connect your phones because of a dead computerized system.

The ECU (electric control unit) cannot receive power from the battery and become unresponsive. In addition, most sensors do not work because ECU cannot sense the input from these devices and work accordingly.

You can see your truck’s rear-view camera and speed sensors stop functioning because of poor signaling and a dead onboard computerized system.

Flickering of lights

Ford F150 trucks are equipped with many interior and exterior lights, making them luxurious and safe for people. The issue comes when these lights become dime and blink during driving.

You can see flickering and dimming of headlights, interior lights, and tailgate lights because of the low voltage supply and electric current.

The dashboard is also equipped with many lights to alert the drivers, which can also start to become dim and flicker.

However, the flickering and dimming of dashboard lights are more challenging because you cannot see the proper warning when some components go bad.

Dead batteries

Alternators charge your truck’s batteries by converting the mechanical current to electric current. In addition, it also converts the DC power source to AC power because most of the electric components need AC.

The batteries become dead when they do not provide sufficient power for charging. In addition, the batteries also drain quickly because of bad charging components.

You cannot even start your vehicle when the batteries die completely. Therefore, it is necessary to check the alternators when you do not start your pickup instead of replacing the batteries.

Battery warning light turns on

The different warning lights on the dashboard alert drivers about malfunctioning or glitches in their respective components. The check light comes on when the voltage decreases from 12 to 14 volts.

I was driving my Ford F150 at night, and my battery or engine check light on the screen worried me.

On checking the engine parts and batteries, I realize that the issue mainly comes from the bad alternators not powering the battery for the smooth running of engine components.

The check engine light or battery light comes on your screen because of a bad alternator, and inspecting them after parking your truck on the safe side is necessary.

Slow performance of electric accessories

Alternator powers most of the electric components of your pickup trucks. The Ford F150 contains many electric accessories to make them comfortable for people.

The electric accessories stress the charging component because they need more electric current to function.

In addition, the electric components in your vehicles also work slowly. For example, you can see that your powered doors take longer to lock and unlock, and sometimes they get stuck.

You cannot close the powered windows by pressing the button on the driver side because of less voltage. Heated and power-adjustable seats also stop functioning because of dead or bad alternators.

Hissing and rattling noise

Alternators contain different parts to recharge the system and convert mechanical current to electric current. However, these parts can wear out with their age and constantly work on converting AC to DC power source.

You can hear the hissing and rattling sound from the hood because of the broken bearing. In addition, the misaligned belts produce a whining and grinding noise.

I also heard the whining noise from my truck while driving, and it was coming when serpentine belts came in contact with a pulley and caused an interruption in their movement.

The worn-out serpentine belts produce uneven sound because of increased friction while moving over the pulley.

Stalling issues

The bad alternators affect the smooth driving of the Ford F150, and you can feel stalling of the engine and sudden loss of power while driving on highways which is uncomfortable.

The issue comes because ignition components and spark plugs do not get enough current or charge to spark the air and gas mixture for a continuous power supply to the engine.

The engine cannot get consistent power because of the poor air and gas mixture burning in the combustion chamber. In addition, the stalling issue is risky when you are on a trip moving uphill and on inclined road surfaces.

Burning smell

I felt the foul burning rubber smell from my Ford F150 truck while driving. I checked the electric components and wirings, and these are almost fine.

The smell was coming from the alternators when I opened the hood to check to overheat in the engines. You can feel the burning smell because of wear and tear in their components.

Drive belts and pulleys are in constant working condition and produce friction. As a result, these components can overheat and cause wear and tear because of the working pressure.

In addition, the chances of wear out in modern vehicles increase because they are equipped with many electric accessories and put a load on their components.

The alternator belt is located near the engine and is more vulnerable to damage because of the heat from the engine parts. Moreover, many people also complain about the burning shoe smell, which comes from the melting of wires and short circuits in them.

The truck start and then turn off 

Many people complain that their Ford F150 won’t start when they turn on the ignition system. In addition, these can stop after some time when you start them.

The problem comes from bad alternators not providing sufficient electric current to charge the batteries. The insufficient charge in batteries cannot ignite the combustion chamber properly to burn air and fuel mixture.

Moreover, I also faced the same issue and heard a murmuring sound while accelerating, and suddenly my truck stopped after this. Therefore, I did not prefer a jump start because it could damage the other parts.

However, the jump-start also does not work when the issue comes because of bad alternators, and you can only drive for a few minutes and the issue comes back.

Related Articles:

Why won’t Ford F150 doors close in winter?

Ford F150 dead batteries symptoms