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25% Off Online Orders of Select Hard Parts. Enter Promo Code MMJ25 in Cart.

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Receive Up To 25% Off Your Online Purchase Of Select Parts And Accessories
Use promotional code MMJ25 at checkout to receive 25% off the following categories: Select Brake Parts, Select Hi-Performance and Truck Accessories, Batteries, Paint, Splash Guards, Select Ventvisors & Bug Shields, Springs & Spacers, Water Pumps, Belts, A/C Parts, Starters, Alternators, Fuel Pumps, Radiators, Radiator Fans, Thermostats, Caps & Clamps, Clutches, Spark Plugs, Plug Wires, CV Axles, Battery Chargers & Booster Cables, OE Locks, Rack & Pinons, Window Motors, RainX Wipers, Appearance Chemicals, Floor Mats, Lift Equipment, Hand Tools, Travel Accessories, Car Covers, Seat Covers, Wheel Covers, Body Repair, Collectibles and Apparel.

Use promotional code MMJ20 at checkout to receive 20% off the following categories: Ignition, Shocks & Struts, Chassis, Jumpstarts, Air Filters, Oil Filters, Bearings & Seals, Engine Parts, Wash Accessories,. Outdoor Lifestyle, Towing, Mini Air Compressors and Tire Repair Accessories.

Offers not valid in combination with any other discounts, promotions or items already on sale. Not valid on gift cards, special orders, installed merchandise, commercial or fleet purchases. Those products that are included in these offers will be displayed in product search results and product detail pages. Excludes the following brands: Champion, Powerstop, Razor, Traxxas, Superchips, Hypertech, Edge, Bully Dog, Diablo, Edelbrock, Holley, NOS, Proform, Specialty Auto, Autometer, Accel, K&N, Kenwood, Pioneer, Sony, Thule, Thule Karrite, JVC, Flowmaster, Hurst, B&M, MSD, Moog, Wagner, Philips and BBK Performance. Valid online until 11:59 PM EST on 10/29/17.

Receive 25% Off Wagner branded brake parts with your online purchase. Use promotional code: WAGNER25.

Receive 10% Off Select Champion, MOOG and FelPro branded products with your online purchase. Use promotional codes: CHAMP10, MOOG10 and/or FELPRO10.

Free Shipping on Orders Over $40 or in-store pickup





The alternator charges the battery and supplies power to various electrical components to keep your vehicle running smoothly. Alternators are typically found near the front of the engine, and are usually driven by the crankshaft via a belt.

What is an Alternator and how does it work

How Does It Work?

  • Alternators produce AC power through electromagnetism which is formed by the stator and rotor relationship.
  • Alternators convert AC current into DC current to power the vehicle?s electrical system and maintain the battery?s correct state of charge.

How Is it Made?

  • The alternators found in most passenger cars and light trucks are relatively small and lightweight.
  • Most are constructed using an aluminum outer housing, as the lightweight metal does not magnetize and can dissipate the tremendous heat generated from producing the electrical power.

Why Does it Fail?

  • Alternators have various moving parts which are subject to stress from heat, cold weather and moisture. As a result, the internal parts gradually wear out.
  • Alternators are subject to contamination from chemicals and its surrounding environment like oil, dirt, salt, etc.

What are the Symptoms of Failure?

  • Dim lights.
  • Drivability or engine performance issues.
  • Warning lights staying lit.
  • Weak or discharged battery.
  • Burnt smell from the alternator.
  • Unusual noise or loud grinding sound coming from the alternator.
  • Malfunctioning of various electrical systems.
  • These symptoms do not necessarily indicate a failed alternator; further testing is always required.

What are the Implications of Failure?

  • Battery drain.
  • Battery can become damaged from an undercharge or overcharge condition and require replacement.
  • Engine stalling/drivability issues.
  • Electrical Charging system failure.
  • Starter motor failure.

How Difficult is the Install?

Difficulty Rating:


  • Some alternators are easily accessible and can be serviced from under the hood while others are located near the bottom of the engine and may require raising the vehicle on a lift to access the alternator for replacement. In some cases, removal of other components such as the tire and wheel assembly, splash guards, drive axle, engine mounts or A/C compressor may be required in order to replace the alternator, which increases the level of diffi culty.

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