A dead battery is one of the most common roadside problems, and a jump-start fixes it in minutes if you do it in the right order. Get the sequence wrong and you risk sparks near the battery or damage to sensitive electronics, so it's worth knowing cold.
Before You Connect Anything
Park the working car close but not touching the dead one, and switch both off. Set both to park or neutral with the parking brakes on. Pop both hoods and find the batteries; on some cars there are remote jump posts under a cover instead. Check that you have a red positive terminal and a black negative on each, marked with plus and minus.
The Connection Order
- Red clamp to the positive terminal of the dead battery.
- Other red clamp to the positive terminal of the good battery.
- Black clamp to the negative terminal of the good battery.
- Final black clamp to an unpainted metal bolt or bracket on the dead car's engine, away from the battery.
That last grounding point, rather than the dead battery's negative post, keeps any spark away from the hydrogen gas a weak battery can vent.
Bring It to Life
Start the working car and let it run for a couple of minutes to feed some charge across. Then try the dead car. If it cranks slowly, wait a bit longer and try again. Once it starts, remove the cables in the exact reverse order, and don't let the clamps touch each other or any metal while the other end is still connected.
Afterward
Drive the revived car for at least 20 minutes, or better yet on the highway, so the alternator can recharge the battery. A jump gets you going, but a battery that died for no clear reason may be near the end. If it happens twice, test the battery and the charging system before you get stranded somewhere worse.