What is the correct sequence when disconnecting and reconnecting a vehicle battery during service?

• A. Disconnect positive first, then negative; reconnect negative first, then positive.
• B. Disconnect the negative (-) cable first, then the positive (+); reconnect positive first, then negative.
• C. Disconnect both wires simultaneously with insulated tools.
• D. Do not disconnect battery at all.

Answer: (B)

The essential idea is to minimize the risk of short circuits and sparks when working with a vehicle’s battery. The negative terminal is tied to the vehicle’s chassis ground, so removing it first breaks the circuit to the frame. That way, if your wrench touches metal while you’re loosening the connections, there’s no path for current to flow through the tool to ground. When reconnecting, attach the positive terminal first to supply power to the electrical system, then attach the negative to complete the circuit and ground the system. This order helps prevent accidental shorts during the process. Always use insulated tools, avoid jewelry, and keep metal objects from bridging terminals.