When servicing components of electrical equipment systems, special precautions must be taken to avoid the risk of failure of semiconductor elements, as well as to prevent electrical injury. Remember that the alternator and starter are directly connected to the battery and can cause a fire if overloaded or short circuited. Try to keep hair and loose pieces of clothing out of the alternator drive belt.
Be sure to remove watches, rings, and other metal jewelry when servicing electrical equipment. Even with the battery disconnected, discharging capacitors by accidentally grounding their terminals can result in electric shock or severe burns.
Do not reverse polarity when connecting the battery. Components such as the alternator or electronic control units contain semiconductor elements that can be damaged if the wires are connected incorrectly.
When starting the engine from an external power source, or connecting the charger, also observe the polarity of the wires.
Never disconnect electrical wiring from the battery, alternator, or diagnostic equipment while the engine is running.
Do not allow the engine to turn over a disconnected generator.
Never test for generator output voltage by grounding its terminals.
Do not use ohmmeters equipped with a manual dynamo to check for continuity in the circuit.
When performing any electrical maintenance work, ensure that the negative cable is disconnected from the battery.
Always disconnect the battery, alternator, and components such as the power/ignition ECM before using arc welding to avoid risk of damage.