How to Jump Start Your Car

It’s finally happened to you. Your car battery is dead, and now it won’t start. Guest blogger Toby Schultz of YourMechanic provides step-by-step instructions for how to jump start your car.

QDT Editor
4-minute read

Jump starting is when you use another person’s running vehicle to give your car enough power to start the engine. Here is a step-by-step guide to jump starting your ride.

First, a warning: Jump starting a vehicle can be very dangerous. There is risk of severe injury or death if not done properly. There is also risk of damage to either car if not done properly. Basically, battery vapors are highly flammable, and in rare cases can cause an explosion of the battery if exposed to an open spark. (As typical automotive batteries charge, they produce and expel hydrogen, which is flammable. If the expelled hydrogen is exposed to an open spark, it can ignite the hydrogen and cause the entire battery to explode.) Proceed with caution and follow all instructions very closely. If at any point you are not 100% comfortable with the process, please contact a professional for help.

Ok, with that said, here we go!

1.    Find somebody with a car that does start, and is willing to help you jump yours. You’re also going to need a set of jumper cables to get the job done.

Note: I suggest wearing protective eyewear and gloves while jump starting any vehicle. Safety first!

2.    Locate the battery in each vehicle. This will usually be under the hood, though some manufacturers put the battery in difficult-to-access areas, such as under the floor in the trunk, or under the seats. If this is the case with either car, there should be remote battery terminals under the hood, which are placed there for the purpose of jump starting or charging the battery. If you cannot locate them, refer to the owner’s manual for help.

3.    Park the running vehicle close enough to the non-running vehicle that the jumper cables can reach between both batteries or remote battery terminals.

4.    Turn the ignition off in both vehicles. Warning: Pay close attention while performing the next steps, and make sure to connect the correct battery leads to the correct terminals of the batteries. Failure to do this could result in explosion or damage to either vehicle’s electrical system.

5.    Clamp one end of the red positive cable to the positive (+) terminal of the good battery.

6.    Clamp the other end of the positive cable to the positive (+) terminal of the dead battery.

7.    Clamp the black negative cable to the negative (-) terminal of the good battery.

8.    Clamp the other end of the black negative cable to a good ground source, such as any unpainted metal part of the engine or car body. Warning: Do not connect the negative cable directly to the negative terminal of the dead battery. There is a risk of spark when the connection is made; if that spark happens near the battery, it could cause an explosion.

9.    Start the car with the good battery. Allow the car to come to a steady idle.

10.    Now you can try to start the car with the dead battery. If the car doesn’t start right up, only crank the engine for 5 to 7 seconds maximum at a time to avoid overheating the starter motor. Be sure to allow a 15- to 20-second break between each attempt to allow the starter to cool.

11.    Once the car starts, leave the engine running. This will allow the vehicle's charging system to begin to recharge the battery. If your car doesn’t start, it’s time to call a mechanic. Skip to step 16 if this is the case.

12.    You may now disconnect the jumper cables. I suggest you remove the cables in the reverse order in which you connected them.

13.    Close the hoods of both vehicles and make sure they are completely latched shut.

14.    Be sure to say thank you to the person who was kind enough to provide you with a vehicle to jump start your car! Without them, none of this would have been possible.

15,    Now you can drive your car. If you only have to drive a short distance, take a longer route to your destination. The idea here is that you want to drive at least 15 to 20 minutes to allow the car’s charging system to sufficiently recharge the battery for the next time you need to start it. Make sure to check all your lights and doors, to see if anything was left on or is staying on, which likely caused the battery to die in the first place.      

16.    It’s time to call a mechanic now. Even if your car started after being jumped, you should have the battery tested to ensure that this doesn’t happen to you again. If your car didn’t start, you will need a mechanic to diagnose the starting problem.


Toby Schultz is a Master Mechanic at YourMechanic, which delivers mobile car repair by certified mechanics in over 300 U.S. cities. Their top-rated technicians can perform over 400 services at your home or office and will even answer your questions online.

Image courtesy of Shutterstock.

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