The alternator is one of many key components in a vehicle's overall operation. This component converts the mechanical energy of the engine transmitted by the engine's serpentine belt into electricity that keeps the battery charged and powers various electric accessories. The alternator features several terminals that require proper identification for a successful installation. Connecting the wrong lead to the wrong terminal can cause damage to the alternator, as well as injury from shock.
Stand the alternator up on its bottom bracket with the pulley side facing toward you and the top bracket facing straight up.
Face the rear of the alternator toward you, and find the threaded stud and nut on the back of the alternator near the top---the location of the output (battery positive) terminal. The battery positive lead connects to this terminal via a ring terminal connector, with the nut holding it in place.
Find the voltage regulator socket located on the side of the alternator at the 3 o'clock position. The voltage regulator connector plugs into this socket.
Find the threaded stud and nut near the 5 o'clock position---the location of the ground terminal connection. The ground lead attaches to this terminal. (Keep in mind that some alternators come without a ground terminal.)
How to Wire an AC Delco 3 Wire Alternator
The AC Delco 3 wire alternator was used in most General Motors products, and many types of heavy equipment, for a long time, which makes it readily available. This alternator has the advantages of high output, compact design and ease of use. With the proper brackets this alternator can be adapted to any vehicle or engine-powered equipment. Wiring this alternator is well within the capabilities of anyone with average mechanical skills.
Disconnect the battery negative terminal.
Connect a length of 10 gauge wire to the output stud on the back of the alternator using a solderless ring connector. Connect the opposite end of this wire to the starter solenoid. Simply connect to the same terminal as the positive battery cable.
Plug the alternator connector in the receptacle on the alternator. Splice a 14 gauge wire to the smaller pigtail from the connector. This wire runs to the IGN terminal of the ignition switch. Connect a small 12 volt warning light in series in this wire.
Splice a 10 gauge wire to the larger wire on the alternator plug. Use a solderless butt connector to make the splice. Make the wire long enough to connect to the same terminal on the starter solenoid as the battery positive cable and the alternator output wire. Connect the wire to the terminal with a solderless ring connector.
