Jack Williams

The Correct Way to Jump Start a Car

It's really important to know how to jump start your car correctly. Failure to take precautions and do things in the correct order can result in an explosion, and injury.

First, you need to prepare for the task carefully:

1. Line both cars up so the batteries are as close as can be without the cars touching each other.

2. Make sure the cars are in park, and both cars are turned off and not touching each other before you connect the cables. Make sure all headlights, blinkers, car radios and A/C's are off. Unplug all accessories from cigarette lighters and power sockets from both cars.

3. Clean off any corrosion from the batteries.

If the battery is cracked and liquid is leaking out, DO NOT go further! Buy a new battery and swap it out. If you try to jump-start a battery that is cracked, it may explode.

Connect the cables in the exact order listed below. Wear eye protection!

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

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

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

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. 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. On this step you'll get a normal spark as you connect the ground.

5. Start the good car's engine; 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.

Remove the jumper cables in the following order:

1. Be careful to avoid letting the cable clamps touch each other:

2. Disconnect the Negative (-) cable from the engine block of the car that was jump-started.

3. Disconnect the other end of the Negative(-) cable from the Negative (-) post of the good battery.

4. Disconnect the Positive (+) cable from the Positive (+) post of the good battery.

5. Disconnect the other end of the Positive (+) cable from the Positive (+) post of the dead battery.

6. 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. 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.

Jack Williams Tire and Auto Service Centers specialize in all of your vehicle's service needs. Whether your vehicle needs factory scheduled maintenance, state inspections or mission inspections, Jack Williams' ASE certified professionals know just how to help you. Visit any of our 29 locations to meet with Jack Williams' team of experts for alignments, brakes, shocks, struts, exhausts, batteries, fluid services, oil changes, filters, belts, hoses, diagnostics and more! Jack Williams Tire is proud to employ ASE certified technicians.