Jump-start safety
Jump-start safety, step by step
Correct cable order, common mistakes around modern electronics, and when a jump start is the wrong answer entirely.
7 min read
The order exists for a reason
Positive to the dead battery, positive to the good battery, negative to the good battery, then the final negative to a solid unpainted engine ground on the dead vehicle. Making the last connection away from the battery keeps a spark away from vented gas.
Modern vehicles are less forgiving
Reversed polarity, even briefly, can damage control modules that are far more expensive than any battery. Follow the jump point locations in the owner manual, since many vehicles route them away from the battery on purpose.
When to stop
A case that is swollen, leaking, or visibly frozen should not be jumped. Repeated jumps in one week are a diagnosis, not a fix. If the vehicle dies again as soon as the cables come off, the charging system deserves attention before the battery does.