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How to jump-start a car

Gloves and eye protection on, jewelry off, and check the dead battery for cracks, bulges or a rotten-egg smell first. Then: red to the dead battery's +, red to the good battery's +, black to the good battery's −, and the last black on bare metal on the dead car, away from the battery. Start the good car, wait 3 to 5 minutes, start yours, then drive 20 to 30 minutes.

Easy15 min to doFree if you have cablesChecked October 3, 2026

Do it like this

Clamp order: red, red, black, metal. 1 dead +, 2 good +, 3 good −, 4 bare metal on the dead car. Take them off in reverse.

Read your owner's manual first. Consumer Reports' chief mechanic says to follow it to the letter, because modern cars' electronics can be damaged by the wrong steps. Source: Consumer Reports Some cars have remote jump terminals under the hood.
Gear up and check. Put on safety glasses and gloves, and take off rings and watches. Look at the dead battery: if it's cracked, bulging or smells like rotten eggs, don't jump it. That battery needs replacing. Source: AAA
Confirm both cars use 12-volt batteries. The voltage is printed on the battery label. Source: AAA
Park close, not touching. Put both cars in park (or neutral for a manual), set the parking brakes, and turn both ignitions off. Source: AAA On a busy road with no room to work clear of traffic, or in darkness or fog, don't try it. Source: AAA
Clamp red to the dead battery's + terminal, then the other red to the good battery's +. Source: AAA Terminals are usually marked + and −. You may need to wipe off grime to see them. Source: Consumer Reports
Clamp black to the good battery's − terminal. Put the last black clamp on clean, unpainted metal on the dead car, like a thick bolt on the engine block, away from the battery. Source: AAA Never clamp it to the dead battery's negative terminal, because that could create a spark. Source: AAA Don't let the clamp ends touch each other. Source: Consumer Reports
Make sure no cables hang near belts or fans. Start the good car and let it run 3 to 5 minutes, then start yours. Source: AAA
Once it starts, leave both running, still connected, for another 3 to 5 minutes. Then remove the clamps in exact reverse order: black from the metal, black from the good car, red from the good car, red from your car. Source: AAA
Drive 20 to 30 minutes without stopping, with the AC and rear defroster off, so the alternator can recharge the battery. Source: AAA

Watch out Don't put the last black clamp on the dead battery itself. The ground point keeps the final spark away from the battery and any fumes. Source: AAA If either car is a hybrid or EV, check its manual first. AAA warns that using one to jump another car can damage its electronics. Source: AAA

If it doesn't work

Cranks slowly? Don't keep trying. Let the good car charge it about 5 more minutes, then try again. Source: AAA
Nothing at all? A bad connection is the most common reason a jump fails. Disconnect safely, scrub whitish-blue corrosion off the posts with a wire brush, check the cables for fraying, and try again. Source: AAA
Still dead after a third try? The battery has likely failed and needs replacing. Call for roadside help. Source: AAA
A single click with bright dash lights often points to the starter. Rapid clicking points to the battery. Starts, then dies after a short drive? Have the alternator checked. Source: AAA
Battery more than three years old? It may not hold a charge overnight. Have it tested right away. Source: AAA Car batteries typically last three to five years. Source: Consumer Reports

Good to know

Say it while you clamp

Red on dead. Red on good. Black on good. Black on metal. Then take them off in the reverse order.

Portable jump starters

A portable jump starter lets you start the car without a second vehicle. Consumer Reports says ones built to handle 140-degree heat cost under $100 and usually hold a charge for months, but you need to check the charge level now and then. Source: Consumer Reports

Where to keep one

Consumer Reports suggests storing a jump starter out of direct sun, for example in the glovebox or trunk. Source: Consumer Reports

Why batteries die

Cars need regular driving so the alternator can keep the battery charged. If a car will sit for a long time, a trickle charger or battery maintainer can help. Source: Consumer Reports

Hybrids and EVs

Hybrids and EVs have a regular 12-volt battery, and that's the only one you can jump. Never touch the high-voltage battery. Check the owner's manual for the right battery or jump terminals. Source: AAA Never use an EV or hybrid to jump another EV. Source: AAA

Sources

AAA How to jump a battery and get yourself back on the road
Consumer Reports How to jump-start a car with a dead battery
Consumer Reports Jump starter buying guide
AAA Oregon/Idaho Jump-starting your car battery: a safe and easy guide
AAA Got hybrid questions?
AAA Club Alliance Jump-starting an EV

Lesson H5.3 · Last checked October 3, 2026 against the sources listed.

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