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How to Jump-Start a Car

Last Modified: November 29, 2018 by Jeff Ostroff

Preparation for Jump-Starting a Dead Car Battery

positive battery terminal
Positive Terminal
negative battery terminal
Negative Terminal

Watch our How to Jump-Start a Car Battery Video

You can access it at CarBuyingTips.com - Dead Battery Video. If you have the YouTube app on your phone you should bookmark this video so you can get to it when you really to need it.

How to Jumpstart a Car Video

Connecting the Car Battery Jumper Cables

The cables must be connected in this exact order listed below. Wear eye protection! Click on the thumbnail pictures for a larger view.

jump-start connections step 1

Step 1: Connect one end of the Positive (+) cable to the Positive (+) post of the dead battery.

jump-start connections step 2

Step 2: Connect the other end of the Positive (+) cable to the Positive (+) post of the good battery.

jump-start connections step 3

Step 3: Connect one end of the Negative (-) cable to the Negative (-) post of the good battery.

jump-start connections step 4

Step 4: Connect the other end of the Negative (-) cable to a good solid shiny, non painted metal part of the engine on the dead car. Usually a bolt on the engine block will do. You want to avoid placing the Negative (-) cable directly on the dead battery to minimize the chance for an explosion. You should only use the post on the dead battery as a last resort. You'll get a spark as you connect the ground, this is normal.

Starting Method

Start the good car's engine and make sure the headlights are off to allow the maximum amount of power to get to the dead battery. Let the good car's engine run a minute or so before attempting to start the dead car. Sometimes you get lucky and the dead car will turn over right away, sometimes it takes a few minutes. If your dead car's interior dome light comes on, it's a great sign that you've connected the cables right. Now shut all doors and dome lights and try to start the car. If it sounds like it's trying to crank but won't turn over completely, give it a few more minutes and rev the engine moderately on the good car. You may also need to play with the cable grips to get a better connection. Normal sparking occurs as you move the cables around. If you couldn't get the dead car to start, see the troubleshooting section further own this page.

Removing the Jumper Cables

Now that your dead car has been successfully jump-started, you can remove the cables in the reverse order that you connected them in. Be careful to avoid letting the cable clamps touch each other:

  1. Disconnect the Negative (-) cable from the engine block of the car that was jump-started.
  2. Disconnect the other end of the Negative(-) cable from the Negative (-) post of the good battery.
  3. Disconnect the Positive (+) cable from the Positive (+) post of the good battery.
  4. Disconnect the other end of the Positive (+) cable from the Positive (+) post of the dead battery.

Check if the Car Can Restart

After your revived car has been running a few minutes, turn off the engine and see if it will restart on its own, no cables attached. This is a good test to see if your charging system is working, and if successful, it's a good indicator that you won't have problems driving home. If the engine cannot crank on it's own, you'll have to jump-start the car again and it may mean you'll have problems getting home. If your car does not restart on its own, it's a sign that something is really wrong, either the battery is bad or your charging system has a problem. Have someone follow you home.

Jump-Start Troubleshooting Tips

If you tried the steps above and your car still won't start it is possible that the dead battery is not getting voltage from the good battery due to bad cables or a bad connection from the good battery.

Auto parts stores can quickly diagnose your dead car battery for free! Have your battery tested before you buy a new battery so you know if it is the problem.

CarBuyingTips.com has affiliate relationships with multiple web sites. We are paid referral fees for leads or sales generated from visitors that click on some links or fill out certain forms on this site. Please view our advertising policy page for more information.