Before welding a chassis on a computer controlled vehicle, what should be disconnected?

• A. Fuel pump
• B. Batteries
• C. Ground strap
• D. Ignition module

Answer: (B)

When welding on a computer-controlled vehicle, the priority is to protect the vehicle’s electrical/electronic systems from welding currents and voltage spikes. Disconnecting the battery removes the primary power source, so no power remains to feed the ECU, sensors, or fuel system. This prevents backfeeding that could damage modules or wiring, and it also reduces the risk of accidental electrical shock or unintended engine cranking if the welding setup were to energize the system. The battery is the most effective single step for isolating all electrical circuits, which is why it’s the best choice.