How to Jump Start a Car in 6 Steps

First, park a vehicle with a full battery close to the car with the discharged battery. The vehicles can be beside each other or facing bumper-to-bumper. They must be close enough to allow the jumper cables to reach the batteries.

Shut off the ignition on both cars and remove the keys. Set the parking brake in both vehicles. Turn off all accessories, including climate control, lights, and radio.

Note: Most gasoline-powered vehicles have batteries under the hood. However, the battery is found in the trunk or under the back seat in some models. Arrange the car with the good battery accordingly. Check the vehicle’s manual if its battery location isn’t known.

Raise the hood of the cars to access the batteries. A car battery has two terminals — positive (+) and negative (-). Sometimes the battery terminals are hidden, and remote metal posts are placed for convenient access to jump the battery or provide a boost. The positive terminal often is identified with a red cap. Refer to the vehicle manual for terminal locations if necessary.

The terminals should be free from corrosion. If the posts seem coated with a white or greenish substance, remove it using a wire brush, aluminum foil, or anything except your bare hand. The corrosion can irritate your skin.

Jumper cables have a pair of spring-loaded clamps at each end — one red and one black. Red clamps attach to positive battery terminals; black clamps are for negative posts or grounding. It’s essential to connect the four clamps securely and in the correct sequence. Improper connection can result in personal injury or damage to the car’s electrical system.

Keep the metal clamps from touching each other while clipping onto the batteries.

How To Connect Jumper Cables

• First, attach a RED clamp to the positive terminal (+) of the DEAD battery.
• Next, attach the RED clamp from the other end of the cables to the BOOSTER battery’s positive terminal (+).
• Then, attach the BLACK clamp to the negative terminal (–) of the BOOSTER battery.
• Last, attach the BLACK clamp to an unpainted metal part on the engine, such as a bolt or bracket, of the car with the DEAD battery. Some models have a grounding bolt marked with a (–) placed solely for this purpose.

Double-check that the connected booster cables aren’t near moving engine parts. Start the engine of the vehicle that’s donating the electricity.

Then, start the car with the weak battery. If the engine doesn’t turn over right away, you might need to wait a few minutes to allow the battery to build a sufficient charge. Increasing the idle speed of the booster vehicle may help make this happen more quickly.

Note: A dead car battery never gets discovered at a convenient time, and foul weather can add to the inconvenience. If you’re wondering if you can jump a car in the rain, don’t worry — it’s safe. Even with the additional moisture, the vehicle battery’s voltage isn’t high enough to make the task more dangerous than jump-starting on a dry day.

• Disconnect the black negative clamp from the jumped car.
• Next, disconnect the black negative clamp from the booster car.
• Then, disconnect the red positive clamp from the booster car.
• Last, disconnect and remove the red positive clamp from the jumped car.

Return the booster cables to your emergency kit and close the car’s hood. Then drive the jump-started car for at least 20 minutes to allow the alternator to charge the jumped battery.

Be sure to park the vehicle in an open area of a safe location when you turn the engine off, in case the car needs jump-starting again. If it does need another jump, the battery’s condition could be deteriorating, especially if it’s more than a few years old.

Many auto parts stores that sell batteries can run a diagnostic check on the car battery to identify whether a replacement is needed.