How to Jump-Start a Car

How to Jump-Start a Car

October 02, 2020

When your ride suddenly won’t start from a dead battery, knowing how to use jumper cables is a good skill to have. At first, jump-starting a car can seem like a stressful situation, but you’ll quickly realize it’s one of the easiest ways to start your vehicle. To bring your battery back to life, all you need is jumper cables and another vehicle with a working battery. Find out how to start a car with these steps below.

1. Review your owner’s manual

Safety should be a priority whenever you’re working under the hood, so always review your owner’s manual before you start hooking up any cables. Your vehicle’s manufacturer will provide specific recommendations and safety precautions to follow when jump-starting.[1]

2. Position the working vehicle

When you’re ready to jump-start your car, you’ll want to position the vehicle with the working battery close enough to your car’s engine so that you can connect jumper cables. If possible, park the working car so that it faces yours, as if each car’s headlights are “staring” at each other. Keep the vehicles about 18 inches apart and make sure they don’t touch. Put both cars in park (or neutral for cars with manual transmission) and remove the keys.[1]

3. Attach the jumper cables

Now that everyone’s parked, it’s time to pop open the hoods and attach the jumper cables. Note the positive and negative terminals on your battery; typically, they’re represented by a + (positive/red) sign and a – (negative/black) sign. Your jumper cables will also have positive/red clamps and negative/black clamps.[1]

For safety purposes, there’s an exact process you need to follow when attaching the cables. Here’s what to do:[2]

  1. Attach the positive/red cable clamp to the dead battery’s positive terminal. Make sure the connection is sturdy.
  2. Attach the other positive/red cable clamp to the working battery’s positive terminal.
  3. Attach the negative/black clamp to the working battery’s negative/black terminal.
  4. Connect the other negative/black clamp to a ground on the vehicle with the dead battery. This can be any unpainted metal surface away from your battery, such as a bolt or engine block. Whatever you do, never connect this clamp to the dead battery’s negative terminal — doing so can potentially cause sparks, which could ignite battery gases and result in the battery exploding.[3]

4. Start the working vehicle

With the jumper cables firmly attached, start the car with the working battery and let it run for a few minutes.[1]

5. Start the dead vehicle

After the car with the working battery has been running for a few minutes, start the car with the dead battery. If it turns on, let it run for at least 20 minutes to allow the battery to recharge.[2]

6. Disconnect the jumper cables

If your vehicle was successfully revived, you can now disconnect the jumper cables. Remove the cables in the reverse order they were attached, as follows:[2]

  1. Negative/black clamp from the previously dead car
  2. Negative/black clamp from the helper car
  3. Positive/red clamp from the helper car
  4. Positive/red clamp from the previously dead car

As you disconnect the jumper cables, make sure the detached clamps don’t touch each other while another clamp is still attached to the vehicle. This can create a major spark that could cause serious injury.[3]

What to do if the car doesn’t jump-start

If your car doesn’t jump-start, check your cable connections and try again. A slightly loose clamp can sometimes prevent a successful jump-start. Corrosion or dirt on the battery terminals may also prevent a good connection.

In the event jump-starting still doesn’t work, you’re probably dealing with a bigger problem. A number of issues could be at hand here, such as a faulty alternator or an old battery that needs replaced. Contact your local mechanic for assistance. (Learning how to extend the life of your car battery will also help for future reference.)

For those times you need a jump-start and can’t do it yourself, being able to call someone for help can be a huge life-saver. See all the ways roadside assistance can give you a hand when you and your vehicle are in a bind.