What is an essential procedure before working on a vehicle's electrical system?

Before working on a vehicle's electrical system, removing the battery terminals is a crucial procedure. This step is vital because it ensures the electrical circuit is completely de-energized, which helps prevent accidental short circuits, electrical shocks, or damage to sensitive computer components in the vehicle. By disconnecting the battery, technicians create a safe working environment where any risk of unintended sparks or shocks when handling wires or components is minimized.

In contrast, the other options do not provide the necessary safety measures specific to electrical work. Disconnecting the radio does not address power to the electrical system overall. Flushing the radiator and checking tire pressure are unrelated procedures to the electrical system and do not serve the primary function of ensuring safety when accessing electrical components.