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What you Need to Know About Mustang Alternators (05-09)

Written By: Chris Bowman

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A new alternator for your Mustang can mean the difference between dropping the bass and having your lights dim when your bumping to your favorite jam. Choose between different power outputs and colors to get the perfect alternator for your ride.

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The alternator in your S197 Mustang is an electromechanical device that converts the spinning mechanical energy of the engines crankshaft (by the way of a belt) into electrical energy. If it were not for the alternator, you would be replacing your (dead) battery every day.

American Muscle

What is the difference between New and Rebuilt?

Alternators, like any other moving part, are prone to wear and tear; because of this, they can fail. When your Mustang’s alternator does die, you have two choices: you can have it rebuilt or you can replace it with a brand new alternator. Rebuilt alternators are usually less expensive and will work perfectly fine for stock applications, but they do not normally come with any type of warranty. The nice thing about choosing a brand new alternator, other than the fact it will be covered by a warranty, is that you can choose to upgrade to higher amperage (AMPs) for more power. 



Black Powermaster Alternator

Why would I need a High AMP Output Alternator?

The alternating current (A/C) created is used to charge the vehicles battery and to power electrical systems such as fuel injectors, headlights and sound system when the engine is running. Simply put: Higher AMP = More Power. If your Mustang is totally stock, you most likely wouldn’t need one. If you have installed a killer stereo, a set of massive sub woofers, or have upgraded any other part of your Mustang’s electrical system, a new high AMP alternator would definitely be beneficial. Any new accessory or upgrade you install that can drain your Mustang’s power will DO just that – drain your power! So if you’re experiencing surging or dimming headlights (especially after installing something like a set of under drive pulleys), you may need to upgrade to a new high output alternator to eliminate charging problems. AmericanMuscle offers a great line of alternators, from 130 AMP to 200 AMP, designed to suit your S197 Mustang power needs.

Blue Chrome Mustang Alternator

Are any accessories needed when installing a High AMP Alternator?

The stock factory alternator wire was not designed to carry the larger loads that a high AMP replacement alternator will produce. So when upgrading your Mustang’s alternator, you should also install a premium power wire at the same time to safely and effectively handle the additional amperage. AmericanMuscle offers the PAPerformance Premium Power Wire Kit, which is made of the highest quality #4 gauge wire and is designed for use on all 2005 to 2009 Mustangs.


Chrome Mustang Alternator

Peace of Mind

  • Higher power output, the more powerful your sound system can be
  • Choose between the less costly rebuilt unit or go with a new, high amp unit
  • 130 amp is a replacement unit
  • 200 amp units should be used for an electrically loaded Mustang


In conclusion, if you have upgraded your Mustang's stereo system, are experiencing charging issues, or worst yet a dead battery, you should strongly consider replacing your stock factory alternator with a higher AMP version for reliable starts, increased charging capacity and peace of mind.


S197 V6 Project Car
Fitment includes: 2005, 2006, 2007, 2008, 2009, GT, V6, ShelbyGT500, Bullitt