Jump-starting Your Car: The Right Way to Do It

You get into your car, and you’re ready to go. There’s just one problem: your car won’t start. Being in this situation is no fun, but sometimes it just means your car needs a good jump start.

Metromile offers roadside assistance as an optional add-on coverage, but if you find yourself without this service or you want to DIY it, here’s how to jump a car. 

How to jump a car

Step 1: Park your car, and make sure the problem is from your car battery.

Before you do anything, you want to make sure that the car battery is actually the problem. If there’s another reason that your car won’t start, then jumping the battery won’t do any good. 

Having dim headlights or a dim dashboard is a good indication that you left the lights on or that the battery needs replacing

Step 2: Take out your jumper cables or buy them.

In order to jump-start your car, you’ll need a set of jumper cables. 

If you don’t have jumper cables, you’ll need to buy them. You can purchase jumper cables at automotive parts and accessory stores, big-box stores, or online with your favorite retailer. Gas stations might sell jumper cables, but they might not be ideal, as they are generally smaller. 

Step 3: Put both vehicles in either Park or Neutral, and shut off the ignition in both cars.

In order to jump a car, you need to have a companion car relatively close to the battery of the dead car. Put both vehicles in park or neutral, and turn off the ignition in both cars. 

Step 4: Take safety precautions.

Safety is a big concern with jumping a battery, so don’t skip any safety steps. You’ll want to take precautions to keep yourself safe.

  • Make sure the car that needs a jump is turned off. You’ll also want to make sure that any electrical items, such as the car lights and radio, are turned off. 
  • You should park the cars closely, but they shouldn’t touch.
  • Inspect the battery before you start. If it is oozing or broken, you’ll likely need to replace the battery. Don’t jump-start your car. Instead, you may need a tow to a repair shop to get a new car battery.
  • If either car battery is corroded, you can usually remove the corrosion from the battery cables and posts with a stiff brush or coarse cloth. It is very important to have clean connections on both batteries before you jump-start your vehicle.
  • Use gloves if you have them to protect your hands.
  • Protect your eyes with a pair of glasses or other eyewear, if possible.
  • Make sure the jumper cables don’t touch each other after they’re connected to the car or during the connection process. The arching can be fatal! The cables should be unwound, not left in a bundle so that you have good control over the clamp ends. 
  • If you don’t have jumper cables in good condition, then consider other options. You should have both a red cable and a black cable. 

Step 5: Attach one of the red clips to the positive terminal of your car.

Find out where each battery is located so that you can get the batteries as close to each other as possible. Some jumper cables are longer than others, so this is especially important if you have short cables. 

Batteries are usually in the front of the car, but this is not always the case. If you’re unsure where your car battery is, double-check your car owner’s manual

If you’re concerned about how to use jumper cables, here’s a quick guide:

  • Each battery will have a positive and a negative terminal, usually prominently marked with a + or – sign. 
  • If you’re curious about what color is positive on jumper cables: The red jumper is positive while a black jumper is negative.
  • Take the red cable clip and place it on the positive terminal of the dead battery. 

Step 6: Attach the other red clip to the positive terminal of the other car.

Next, you want to take the other end of the red cable clip to the positive terminal on the working battery of the other car. 

Step 7: Attach one of the black clips to the negative terminal on the other battery.

Then, attach one of the black clips to the negative terminal on the car with the good battery. 

Step 8: Attach the last black clip to an unpainted metal surface on your car that isn’t near the battery.

This following sequence is a really important one because this will close the circuit. If the black cable is connected to the dead battery’s negative post, then you risk igniting the gas that is coming off of the battery.

Look for an exposed, unpainted metal surface, such as a battery bolt or other shiny metal attached to the engine. If nothing is apparent, then the negative post may be used as a last resort.

Keep the cables away from the engine so that moving parts don’t damage the jumper cables and so that the clamps don’t touch each other. Here’s an image of how to hook up jumper cables:

Source: Dummies

Step 9: Start the working vehicle and let the engine run for a few minutes.

The next step is to start the working car first and let it run idle for a few minutes. 

Rev your car a little, but not too much; 30 to 60 seconds is enough. This will actually charge the dead battery, even if the car hasn’t started up yet. 

Step 10: Try to start your vehicle.

After letting the working vehicle run for a bit, try to start the disabled car. 

If that doesn’t seem to work, then turn off both of the engines. Then, disconnect the last-connected cable, and try to secure the connections again. This time around, you want to use a longer “charging” period by running the engine at a high idle for up to five minutes. 

If the car still doesn’t work, you may need to replace the car battery. 

Step 11: Learn how to remove jumper cables.

After you’ve confirmed everything is running smoothly, you’ll need to remove the jumper cables. 

To start, take the negative black clips off the cable. To disconnect jumper cables safely, start with the negative cables first, and then move onto the positive cables. 

Remember: The cables shouldn’t touch while attached to the cars. 

The bottom line 

If your car won’t start and you need to learn how to jump a car or how to use jumper cables on the fly, it can be a bit scary. But using these steps, you can learn how to hook up jumper cables and how to disconnect jumper cables safely.

If you want additional support with roadside assistance, check out Metromile and get an online quote for affordable pay-as-you-go car insurance. Drivers can save 47% on average when they switch to Metromile, according to a 2018 survey of new customers who saved with Metromile. 

Melanie Lockert is a freelance writer, podcast host of the Mental Health and Wealth show, and author of Dear Debt. She’s a cat mom to two jazzy cats, Miles and Thelonious, an amateur boxer, music lover, and needs coffee to function