Jump-start a car with a dead 12-volt battery — connect and disconnect jumper cables

You need a suitable assisting car, undamaged jumper cables rated for your vehicle, and safety glasses. Do not attempt to jump-start a frozen, cracked, swollen, or leaking battery. Keep cigarettes, flames, and sparks away. Remove metal jewelry. If you find damage or are unsure, contact roadside assistance.

Park in a safe outdoor location, close enough for the cables to reach but without the cars touching. Select Park or Neutral, apply both parking brakes, and switch off the engines, ignitions, and unnecessary electrical accessories.

Use the manuals to identify the positive (+) terminals, the assisting battery’s negative (−) connection, and the disabled car’s designated ground or negative jump-start point. Do not rely on colors alone. Use designated jump-start points where provided. Keep cables clear of fans, belts, and hot parts; cooling fans can start automatically.

Attach the first red clamp to the assisting car’s specified positive (+) connection. Keep the loose clamp away from metal and other clamps.

Attach the other red clamp to the disabled car’s positive (+) connection. The red cable now connects positive to positive.

Attach the first black clamp to the assisting car’s specified negative (−) connection.

Attach the remaining black clamp to the disabled car’s designated ground point, away from the battery. Do not use the battery’s negative terminal unless the manual explicitly instructs you to. Never connect to fuel lines or moving parts. Check that all clamps are secure.

Follow the manuals’ instructions on running the assisting car’s engine and how long to wait. Commonly, the assisting engine is started and allowed to run for a few minutes, but manufacturers may specify a different procedure. Check particularly whether the assisting engine should remain running during the start attempt.

Start the car normally. Do not touch the clamps during the attempt. Follow the manual’s limits for cranking time and pauses between attempts. If the car will not start after a couple of short attempts, stop and contact roadside assistance. Also stop if you notice smoke, excessive sparking, or hot cables.

Once the disabled car’s engine is running steadily, prepare to disconnect the cables. Leave it running unless its manual says otherwise. Keep hands, clothing, and cables clear of moving and hot parts. Never allow loose clamps to touch each other or other metal.

First remove the black clamp from the previously disabled car’s ground point. Hold the clamp clear.

Remove the black clamp from the assisting car’s negative connection. Put the black cable safely aside.

Remove the red clamp from the previously disabled car’s positive connection. The cable is still connected to the assisting car: do not let the loose clamp touch metal.

Finally, remove the red clamp from the assisting car’s positive connection. Put the cable away and replace the terminal covers. Check that both engine compartments are clear before closing the hoods.

A successful start does not mean the battery is fully charged. Arrange a full charge using a compatible battery charger according to the manual; a short drive may not be enough. Have the battery and charging system tested if the problem returns. If the charging warning light stays on or the car stops again, contact roadside assistance.