How to Jump Start a Dead Battery
By Pablo Zaldivar · Junior's Auto Repair, Twin Falls, ID
What You'll Need
⚠️ Before you start: Never jump-start a cracked, leaking, or frozen battery — it can explode. Some modern vehicles have special jump-start terminals under the hood rather than directly on the battery. Check your owner's manual if you're unsure.
Position the vehicles and turn both engines off
Pull the working vehicle close enough for your cables to reach both batteries comfortably — usually nose to nose or side by side. Turn both vehicles completely off. Make sure they're not touching each other.
Identify the positive and negative terminals
On each battery, find the positive terminal (marked with a '+' and usually has a red cover) and the negative terminal (marked with a '-', usually black). Your jumper cables are also color-coded: red for positive, black for negative.
Connect the red cable to the dead battery's positive terminal
Clamp one end of the red cable firmly to the positive terminal of the dead battery. Make sure you have a solid connection — a weak grip can cause sparking.
Connect the other red cable end to the good battery's positive terminal
Take the other red clamp and connect it to the positive terminal of the working vehicle's battery. Again, make it a firm connection.
Connect the black cable to the good battery's negative terminal
Now switch to the black cable. Clamp one end to the negative terminal of the good battery.
Clamp the last black cable to an unpainted metal ground on the dead car
This is the most important step people get wrong. Do NOT connect the final black clamp to the dead battery's negative terminal. Instead, attach it to an unpainted metal part of the dead car's engine — a bolt on the engine block or a metal bracket works well. This prevents sparks near the battery.
Start the working car, wait a few minutes, then start the dead one
Let the working car run for 2–3 minutes. Then try to start the dead vehicle. If it starts, let it run for at least 15–20 minutes (or take a short drive) to let the alternator recharge the battery. Remove the cables in the reverse order you connected them: black from ground, black from good battery, red from good battery, red from formerly dead battery.
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