To Chang an alternator is an eight (8) step process.

Safety Issues: The alternator is one of the major components of an electrical system in a vehicle. Before any repairs/replacement of the alternator can be started, all electrical power must be disconnected. The simplest and best way to do this is to remove one of the battery lugs (commonly this is the black negative ground wire). In practice, many mechanics may switch off the ignition switch only, however the disconnection of the battery lug is a preferred method.

At this time, all electrical connections to the alternator should be removed. Sometimes it’s necessary to remove other engine components to get access to the alternator (like hoses from the emissions system). Note these positions as they will have to be re-attached later.

Note the Belts and Tensionsers Positions: Most alternators are turned by a belt. This can be a single “Vee” belt or a “serpentine” belt. This belt sometimes also turns other engine components, thus, its position must be noted as this would be used during the re-installation process.

Loosen Bolts: At this time, typically there are two long bolts that attach the alternation to the engine, while allowing it leeway to move up and down. There is a tensioner attached to the belt. This tensioner pushes outwards on the belt, keeping it taut. Unless it is absolutely necessary, this tensioner is not touched.
Remove the Belt: After removing the above mentioned bolts, the belt can be slipped off to the side. It’s not necessary to completely remove the belt, especially if it’s also set to turn other engine components. At this stage, the alternator should have been completely freed and can be removed.

Replace alternator: To complete the change of the alternator, the new alternator is attached to the engine body by one bolt. At this time, the belt is slipped onto the pulley. It may be necessary at times to use a bar as leverage to push the alternator into place, especially when trying to get the belt into position. With the belt in position, the bar again is used to raise the alternator, while the second bolt is attached. A helping hand is good at this time, as it’s difficult to use the raising bar and trying to attach the second bolt at the same time.
Electrical Connections: Once the alternator, belt, and tensioner are back in its original position, then it’s time to reconnect the any hoses and components that were loosened during the installation process. At this stage, the electrical connections are also re-attached.
Testing: After the complete re-installation of the alternator, the battery cable should be re-attached after making a quick scan of the engine area to ensure that no tools etc are left on the engine compartment. The engine should be started, and the charging light should be off. This is an indication that the alternator is working and is producing current.

With a helping hand again, the engine should be brought up to 1000 rpm, and a multi-meter should be attached to the battery terminals. At 1000 rpm, the reading should be approximately 14 volts dc, which is indicative of a properly functioning charging system.

Recycling: The old alternator should be returned to the parts depot where the new alternator has been bought from. If the old alternator is in a general good condition for rebuilding, then a core charge of between $50 to 75 can be refunded.