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Jump-Starting a Car - Part 2

Last Modified: December 04, 2015 by Jeff Ostroff

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.