To prevent damage to the alternator and regulator, the following precautionary measures must be taken when working with the electrical system.
Never reverse battery connections. Always check the battery polarity visually. This should be done before any connections are made to be sure that all of the connections correspond to the battery ground polarity of the truck.
Booster batteries for starting must be connected properly. Make sure that the positive cable of the booster battery is connected to the positive terminal of the battery that is getting the boost. The same applies to the negative cables.
Disconnect the battery cables before using a fast charger; the charger has a tendency to force current through the diodes in the opposite direction for which they were designed. This burns out the diodes.
Never use a fast charger as a booster for starting the vehicle.
Never disconnect the voltage regulator while the engine is running.
Do not ground the alternator output terminal.
Do not operate the alternator on an open circuit with the field energized.
Do not attempt to polarize an alternator.