How to Replace the Alternator on a 2006 to 2014 Ford F-150

Your Ford F-150’s alternator charges the battery to help start your truck, and provides power to your truck’s electrical accessories while the engine is running, which includes the power windows, radio, windshield wipers, and more. When the alternator fails, your F-150’s electrical systems and engine will only stay on until the battery's reserve charge is depleted. Your truck may die, but you might be able to restart it with a jump start or by charging the battery. If you need to replace the alternator for your 2012 Ford F-150 5.0-liter V8 , you may notice dim headlights or that your battery is not staying fully charged. Our step-by-step instructions will help you perform an alternator replacement on your Ford F-150 to keep your truck starting and running as it should.

Tools & Materials List

Step by Step Instructions

Remove the Alternator

Install the New Alternator

Additional Resources

Tools & Materials

Safety Eye Glasses Safety Glasses
Protective Gloves Nitrile Gloves
Ratchets Ratchets
Sockets for changing spark plugs Sockets
Alternator Alternator

Step-by-Step Instructions to Replace the Alternator on a 2006 to 2014 Ford F-150

Today we’ll be working on this 2012 F-150, but the repair should be similar for any Ford truck equipped with a 5.0 liter engine. The alternator on your truck charges the battery and runs the electrical accessories when the engine is running. A failing alternator can cause the lights on your F-150 to dim, the windows or radio may not work as well as they should, your battery may not fully charge, and if the alternator has failed entirely, the truck may stall when the battery’s reserve capacity has been depleted. If you’re not completely comfortable doing this yourself, we’d be happy to recommend a professional technician in your area.

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Remove the Alternator

O’Reilly Auto Parts mechanic opening the hood of a 2012 Ford F-150

Step 1: Open the Hood

Park on a level surface and open the hood.
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Mechanic using a ratchet and socket to remove a negative terminal on a SuperStart battery

Step 2: Remove the Negative Battery Terminal

The first thing to do is to remove the negative terminal from your battery, which is good practice during any electrical repair on your truck. Set the negative terminal aside where it won’t touch metal.
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Chris from O’Reilly Auto Parts using a ratchet to remove the air intake tube

Step 3: Remove the Air Intake Tube

For easier access to the alternator, disconnect the hoses and electrical connector, then remove the air intake tube.
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Mechanic using a breaker bar to relieve tension on the serpentine belt

Step 4: Remove the Serpentine Belt

To remove the main serpentine belt connected to your alternator, use your breaker bar and a 13mm socket on the tensioner pulley bolt and rotate counterclockwise to relieve tension on the belt. Then slide the belt off of the pulleys.
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Chris from O’Reilly Auto Parts removing a drive belt tensioner with a ratchet

Step 5: Remove the Tensione

Remove the bolt from the drive belt tensioner and set the tensioner aside.
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Mechanic using an extended socket and ratchet to remove the upper alternator bolt

Step 6: Remove the Alternator Bolts

To make accessing the electrical connector easier, first use your 15mm socket to remove the upper alternator bolt, then the lower alternator bolt.
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Mechanic disconnecting the battery cable and electrical connector

Step 7: Disconnect the Battery Cable and Electrical Connector

Now you can remove the battery terminal from your alternator by pushing the protective boot aside and using a 13mm socket and ratchet to remove the retaining nut. After disconnecting the battery terminal, disconnect the electrical connector from the back of the alternator.

At this point, you should be able to grasp the alternator and remove it from the engine compartment.

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Install the New Alternator

Mechanic comparing the new and old alternator side-by-side

Step 8: Ensure the Proper Dimensions

Before installation, ensure the new alternator fits your vehicle properly and compare to your old alternator.
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Chris from O’Reilly Auto Parts securing the retaining nut on the battery cable

Step 9: Reinstall the Electrical Connector and Battery Cable

To install your new alternator, reconnect the electrical connector at the back of the alternator. Then reinstall the battery cable and retaining nut. Torque the retaining nut to 150 inch pounds.
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Man using a ratchet to install the alternator bolts

Step 10: Reinstall the Upper and Lower Alternator Bolts

Reinstall the upper and lower alternator bolts. Torque both of these bolts to 35 foot pounds.
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Man installing a new tensioner into position with a ratchet

Step 11: Reinstall the Drive Belt Tensioner

Reinstall the drive belt tensioner and torque the bolt to 35 foot pounds.
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Breaker bar inserted into the tensioner to install the new serpentine belt

Step 12: Reinstall the Serpentine Belt

Now, you can reinstall the drive belt by looping it over every pulley according to the routing diagram, but you’ll need to leave it off the water pump pulley for now. Use your breaker bar and turn the tensioner counterclockwise. Now you can reinstall the belt over the water pump pulley, then slowly release the tensioner and remove your breaker bar.
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Mechanic holding the air intake tube above the engine and then attaching the hose to the outlet

Step 13: Reinstall the Air Intake Tube

Reinstall the air intake tube, hoses, and electrical connector.
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Mechanic using a ratchet to attach the negative battery terminal

Step 14: Reconnect the Negative Battery Terminal

Reconnect the negative terminal to your battery and start your vehicle. If it is running the way it should be, close the hood.
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Additional Resources

Serpentine Belt

How to Replace the Serpentine Belt, Tensioner, and Idler Pulley on a 2009 to 2014 Ford F-150
how to replace water pump additional resource

How to Replace the Water Pump on a 2009 to 2017 Ford F-150
Thermostat

How to Replace the Thermostat in a 2009 to 2017 Ford F-150

These step-by-step instructions and video detail an alternator replacement on a 2012 Ford F-150, and will be similar to replacement procedures on 2006, 2007, 2008, 2009, 2010, 2011, 2013 and 2014 Ford F-150s equipped with a 5.0-liter engine. The replacement procedures will also be similar for select Ford F-150 FX2, FX4, King Ranch, Lariat, Platinum, STX, XL, and XLT models with a 5.0L engine from 2011, 2012, 2013, and 2014. Replacing a damaged or failing alternator helps you maintain a safe, functioning electrical system, and can keep your truck’s electrical accessories working and your battery charged. If you notice your truck’s headlights or dashboard lights are dim, or if your truck’s battery is not staying fully charged, you should test and replace your alternator as soon as possible to prevent stalling or a breakdown due to a loss of battery reserve charge.

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The automotive repair work depicted in this series is performed under the direction of the manufacturer of the product featured. Prior to undertaking any of the demonstrated repairs on your vehicle, we suggest you consult with a certified mechanic or another professional who can adequately advise you of the proper repair or remedy required. O’Reilly Automotive Stores, Inc. and its affiliates (“O’Reilly”) disclaims any responsibility for injury or damage resulting from a viewer’s attempt to recreate the repairs shown in this series.

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