Alternator Replacement

Step by step guide on how to replace an automotive alternator. This article pertains to most non-hybrid or electric cars.

Difficulty Scale: 3 of 10

Tools and Supplies Needed

  • Wrench set
  • Sockets and ratchet set
  • Replacement Alternator
  • Shop towels
Park your car on level ground with the engine off and the emergency brake on. If needed, raise a car according to the manufacturers recommended instructions and secure with jack stands.


Step 1 - Locate and disconnect the negative battery cable.

Step 2 - Remove serpentine belt, please visit - Removing Serpentine Belt

Step 3 - At the rear of the alternator unplug or unbolt the wiring from the terminals. (Note: If wiring is difficult to access, you will be able to disconnect the wiring later in the removal.)

Step 4 - Once the serpentine belt has been removed, loosen and remove all mounting bolts securing the alternator to the mounting bracket.

Step 5 - After all bolts are removed, slide the alternator out and away from the mounting bracket.

Step 6 - Match the failed alternator to the replacement unit including the wiring plugs or connectors.

Step 7 - Reverse the order of removal steps to install the new alternator.

Helpful Information
When an alternator fails, it will cause the battery to lose its charge which will cause the engine to stall or not crank over. A common indication the alternator needs to be replaced is that a warning light on the dash has come on informing the driver there is a problem with the charging system. Most alternator replacements are relatively simple and can be done with everyday tools.

Best Practices

  • Return the used alternator to the parts store to avoid paying the core charge.
  • Use quality replacement parts to ensure proper operation


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


Please use our question form if you have a specific question about your car as we are not able to give you a full answer on this page.

Article first published (Updated 2015-01-05)