How to jump a dead car, in the order it really happens

What the box says

Connect the cables in the order shown. Start the working vehicle. Start the disabled vehicle. Drive away.

Four sentences. The diagram has two smiling cars and no weather.

What you will actually need

• Jumper cables. Heavy ones. 4- or 6-gauge, 16 to 20 feet long. The skinny 10-gauge set that came free with something will get warm and accomplish very little.
• A second car with a good battery, and a person willing to park it nose to nose with yours.
• Safety glasses. The ones in your garage count. The ones on your head don't.
• Gloves. Batteries are dirty and the clamps bite.
• A flashlight, because no battery has ever died at noon.
• A wire brush or an old toothbrush for corroded terminals.
• Your owner's manual. Some cars hide the battery in the trunk or under a seat and give you a separate jump post under the hood. The manual knows. You don't.
• The cables themselves, again. This is the thing everybody forgets. They're in the other car. They're always in the other car.

My wife keeps a set in her SUV and a set in the garage, and she's never once had to borrow a stranger's. I have borrowed a stranger's. Twice. Put a set in what belongs in your trunk from November to March and leave them there.

The steps

1. Make sure it's actually the battery. Turn the key. A rapid click-click-click, a slow groaning crank, or dim dash lights point to a weak battery. If the engine cranks strong and fast but won't fire, a jump won't help. That's fuel, spark or something else.

This is the step where you realize the dome light has been on since Tuesday.

2. Position the cars. Park the donor close enough for the cables to reach, but don't let the vehicles touch. Both cars off, in Park (or in gear with the parking brake set on a manual), keys out. Headlights, radio, heater fan and wipers off in both.

Pull in once, decide it's too far, pull in again, decide it's too close. Two adjustments is normal. Five means somebody's watching.

3. Check the battery before you touch it. Put on your glasses. If the dead battery is cracked, leaking, bulging or visibly frozen, stop. Don't jump it. Batteries can vent hydrogen gas, which is explosive. No smoking, no open flame, no lighter for extra light.

4. Find the terminals. Pop both hoods. Positive is marked + and usually has a red cover. Negative is marked −. If the terminals are crusted with white or green powder, brush them until you see metal. If your manual shows a remote jump post, use that instead of the battery itself.

The hood release is the lever by your left knee with a tiny drawing of a car yawning. The second latch is under the front lip, roughly where you weren't feeling around.

5. Red clamp to the dead battery's positive (+). Firm grip on clean metal.

Grandpa's rule: red to dead. He said it every time, and he was right every time.

6. Other red clamp to the good battery's positive (+).

7. Black clamp to the good battery's negative (−).

8. Last black clamp to bare, unpainted metal on the dead car, like a solid bolt or bracket on the engine block, well away from the battery. Not to the dead battery's negative post. That final connection can spark, and you want any spark far from a battery that may be venting gas. Keep the cables clear of fans and belts.

9. Start the donor car. Let it idle for a few minutes, a touch above idle if you can. You're putting a little charge into the dead battery before you ask it to crank.

This is the long, quiet stretch where you and the donor exchange weather opinions over two open hoods.

10. Try the dead car. Crank for no more than about five to ten seconds. If it doesn't catch, wait a couple of minutes and try again. After three or four failed tries, stop. You're cooking the starter and the donor's patience.

11. Disconnect in exact reverse order. Black from the ground point. Black from the donor. Red from the donor. Red from the formerly dead car. Never let the clamps touch each other or any metal while either end is still connected.

The urge to yank all four at once and wave goodbye is strong. Resist it.

12. Keep the revived car running. Drive for at least 20 to 30 minutes without shutting it off at the gas station. Then get the battery tested. Many auto parts stores will check it for you. A jump gets you home. It doesn't fix the reason you needed one.

Where it goes wrong

It clicks but still won't start. Almost always a bad connection. Wiggle each clamp until it bites into clean metal, move the ground clamp to a better bolt, and let the donor run a few minutes longer. Thin, cheap cables can also simply fail to carry enough current. That's the free set from step one, getting its revenge.

It starts, then dies the next morning. The battery is likely worn out, or something is draining it, or the alternator isn't charging. Batteries usually last somewhere around three to five years, less in hard heat or cold. Get the battery and charging system tested before you plan your week around it. The car servicing that can't wait, and the kind that can covers what else to watch.

You crossed the cables. Reversed polarity can blow fuses and damage electronics. If you see sparks, smoke or smell something hot the moment you connect, disconnect immediately in reverse order. Check the fuses, and if things don't work afterward, let a shop look at it. This is why you read the + and − twice, out loud, like a pilot.

When to call a pro

• The battery is cracked, leaking, swollen or frozen.
• You drive a hybrid or electric vehicle and the manual doesn't clearly explain jumping it. Many hybrids have specific procedures, and some shouldn't be used as donors at all.
• You can't find the terminals or the jump post, or they're badly corroded and loose.
• It needed a jump twice in one week.
• Anything smells like burning or you see smoke.

Check whether your insurance, car club or the manufacturer includes roadside assistance. A lot of people pay for it and forget. If you'd rather not depend on a second car at all, a portable jump starter pack is a solid backup. Charge it every few months.

And when somebody gives you a jump, do what decent people have always done. Thank them properly, offer to return the favor, and next time it's you with the good battery in the grocery store lot, be the one who walks over with the cables.

Assuming you remembered where you put them.