Several precautions must be observed when performing work on alternator equipment.
If the battery is removed for any reason, make sure that it is reconnected with the correct polarity. Reversing the battery connections may result in damage to the one-way rectifiers.
Never operate the alternator with the main circuit broken. Make sure that the battery, alternator, and regulator leads are not disconnected while the engine is running.
Never attempt to polarize an alternator.
When charging a battery that is installed in the vehicle, disconnect the negative battery cable.
When utilizing a booster battery as a starting aid, always connect it in parallel; negative to negative, and positive to positive.
When arc (electric) welding is to be performed on any part of the vehicle, disconnect the negative battery cable and alternator leads.
Never unplug the PCM while the engine is running or with the ignition in the
position. Severe and expensive damage may result within the solid state equipment.