how to connect jumper leads to car

Dead battery? Right, let’s play spark-safe Lego.

With both cars off, connect the red lead to the flat battery’s +, then the other red to the donor’s +; black lead to the donor’s −, and the final black to bare metal on the dead car (not its − post). Start the donor, wait a minute or two, then start the stricken car and let it idle politely. Remove the leads in reverse order—black from the grounded point, black from donor, red from donor, red from the revived battery—without letting clamps kiss. If yours is a hybrid, stop‑start, or has a marked jump terminal, use that and obey the manual, because fried ECUs are expensive and swear‑word inducing. Bulging, leaking, or rotten-egg-smelling batteries are a hard no—call roadside assist instead.