Quick TakeawayJump starting a car looks simple, but doing it wrong can damage electronics or mask a bigger problem. Here's how to do it properly — and when to skip it.
Introduction
Jump starting a car is one of those tasks that looks foolproof until the cables are in your hands and you're second-guessing the order of connections. Getting it wrong doesn't usually cause a dramatic problem, but it can — sparking near the battery, damage to sensitive electronics, or a jump that "works" for ten minutes before the car dies again at the next red light.
What You Need Before Starting
• A second, running vehicle with a healthy battery, or a portable jump starter pack • Jumper cables in good condition (no exposed or corroded clamps) • Both vehicles in park or neutral with the parking brake engaged and engines off before connecting
The Correct Connection Order
Getting the sequence right matters more than most people assume:
• Connect the red (positive) clamp to the positive terminal of the dead battery. • Connect the other red clamp to the positive terminal of the good battery. • Connect the black (negative) clamp to the negative terminal of the good battery. • Connect the final black clamp to an unpainted metal surface on the dead car's engine block — not the dead battery's negative terminal.
That last step surprises a lot of people. Grounding the final connection away from the battery itself reduces the risk of sparking directly near the battery, which can be dangerous if the battery has been venting gas.
Starting the Process
With connections made, start the working vehicle first and let it run for a couple of minutes before attempting to start the dead vehicle. This gives the flat battery a small initial charge rather than asking it to deliver full cranking power from a completely dead state.
Then attempt to start the dead vehicle. If it doesn't start on the first or second attempt, stop — repeated cranking attempts can strain the starter motor and won't succeed if the battery is too deeply discharged or genuinely failed.