How To Jump a Car Quick Tips
- You must connect jumper cable clamps securely and in the correct sequence to reduce risk of personal injury or damaging the car’s electrical system.
- After jump-starting the car, disconnect the cables in reverse order and drive the vehicle for 20 minutes to allow the alternator to charge the jumped battery.
- Cars that won’t jump-start might need a new battery or a new starter.
- Do not attempt to jump the battery if it is cracked or leaking.
Knowing how to jump a car battery is a basic skill that every driver needs. Like fixing a flat, jumping your car isn’t something that’s done regularly and never at a convenient time. With some knowledge and by following a few simple steps, it doesn’t take long to jump-start a car. You can be back on the road in a matter of minutes.
Jump-starting a car requires jumper cables, also known as booster cables, to connect the dead battery in your car to a fully charged battery in another vehicle. It’s a great idea to keep a good set of cables along with other roadside emergency equipment in the trunk of your car.
Read on to learn how to jump-start a car using these instructions.
6 Steps To Jumping a Car with a Dead Battery
1. Position the Booster Vehicle
2. Locate Battery Terminals
3. Connect Jumper Cables
4. Jump-Start the Car
5. Disconnect Jumper Cables
6. Drive the Jumped Car
1. Position the Booster Vehicle
First, park a vehicle with a full battery close to the car with the discharged battery. The vehicles can be beside each other or facing bumper-to-bumper. They must be close enough to allow the jumper cables to reach the batteries.
Shut off the ignition on both cars and remove the keys. Set the emergency brake in both vehicles. Turn off all accessories, including climate control, lights, and radio.
Note: Most gasoline-powered vehicles have batteries under the hood. However, the battery is found in the trunk or under the back seat in some models. Arrange the car with the good battery accordingly. Check the vehicle’s manual if its battery location isn’t known.
2. Locate Battery Terminals
Raise the hood of the cars to access the batteries. A car battery has two terminals — positive (+) and negative (-). Sometimes the battery terminals are hidden, and remote metal posts are placed for convenient access to jump the battery or provide a boost. The positive terminal often is identified with a red cap. Refer to the vehicle manual for terminal locations if necessary.
The terminals should be free from corrosion. If the posts seem coated with a white or greenish substance, remove it using a wire brush, aluminum foil, or anything except your bare hand. The corrosion can irritate your skin.
Do not attempt to jump the battery if it is cracked or leaking.
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3. Connect Jumper Cables
Jumper cables have a pair of spring-loaded clamps at each end — one red and one black. Red clamps attach to positive battery terminals; black clamps are for negative posts or grounding. It’s essential to connect the four clamps securely and in the correct sequence. Improper connection can result in personal injury or damage to the car’s electrical system.
Keep the metal clamps from touching each other while clipping onto the batteries.
How to Connect Jumper Cables
- First, attach a RED clamp to the positive terminal (+) of the DEAD battery.
- Next, attach the RED clamp from the other end of the cables to the BOOSTER battery’s positive terminal (+).
- Then, attach the BLACK clamp to the negative terminal (–) of the BOOSTER battery.
- Last, attach the BLACK clamp to an unpainted metal part on the engine, such as a bolt or bracket, of the car with the DEAD battery. Some models have a grounding bolt marked with a (–) placed solely for this purpose.
4. Jump-Start the Car
Double-check that the connected booster cables aren’t near moving engine parts. Start the engine of the vehicle that’s donating the electricity.
Then, start the car with the weak battery. If the engine doesn’t turn over right away, you might need to wait a few minutes to allow the battery to build a sufficient charge. Increasing the idle speed of the booster vehicle may help make this happen more quickly.
Note: A dead car battery never gets discovered at a convenient time, and foul weather can add to the inconvenience. If you’re wondering if you can jump a car in the rain, don’t worry — it’s safe. Even with the additional moisture, the vehicle battery’s voltage isn’t high enough to make the task more dangerous than jump-starting on a dry day.
5. Disconnect Jumper Cables
With the jump-started car’s engine running at a smooth idle, disconnect the jumper cables in the reverse order they were attached. Always keep the metal clamps from touching each other when connecting and disconnecting them from battery terminals.
- Disconnect the black negative clamp from the jumped car.
- Next, disconnect the black negative clamp from the booster car.
- Then, disconnect the red positive clamp from the booster car.
- Last, disconnect and remove the red positive clamp from the jumped car.
6. Drive the Jumped Car
Return the emergency cables to your emergency kit and close the car’s hood. Then drive the jump-started car for at least 20 minutes to allow the alternator to charge the jumped battery.
Be sure to park the vehicle in an open area of a safe location when you turn the engine off, in case the car needs jump-starting again. If it does need another jump, the battery’s condition could be deteriorating, especially if it’s more than a few years old.
Many auto parts stores that sell batteries can run a diagnostic check on the car battery to identify whether a replacement is needed.
MORE: Why Won’t My Car Start?
Jumping a Hybrid Car or Electric Vehicle
With the number of electric cars on the road increasing, more people ask if or how you jump a car if it’s a hybrid. The simple answer is that an electric car or hybrid vehicle gets jump-started using a process similar to a traditional gas-powered car.
It’s important to note that hybrids have two batteries: A 12-volt battery — like a traditional car battery — and the more robust setup that powers the electric motor.
Many manufacturers have located hybrids’ auxiliary 12-volt battery in unusual places. Some have placed jump-start tabs under the hood in the fuse box for convenience. Because this varies by make and model, it’s best to refer to the vehicle’s manual for guidance on jump-starting a hybrid.
EVs have a similar situation. A 12-volt battery keeps electronics working while the EV is powered down. If this gets discharged, it could use a jump to get the motor working. You won’t be able to jump-start an EV using a second EV, even if they are the same brand.
The 12-volt system on electric vehicles isn’t designed to provide this kind of service to a second EV.
TIP: Use a gas-powered car or a portable jump-start device when faced with a dead electric car battery.
What To Do if Your Car Won’t Jump
So you’ve learned how to jump a car, but what happens if the car won’t jump start? Several situations may cause an unsuccessful jump.
- Double-check the booster cable connections and remove corrosion from the battery terminals to ensure good contact.
- Batteries can fail or be so old and weak that a jump doesn’t help. Replacing the battery might be necessary. A new battery can cost $250 or more.
- Hearing a clicking sound when trying to jump-start the car may indicate that the starter needs replacing. Expect to pay about $750 for a starter replacement at a dealership service center.
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- Is My Car Battery Dead?
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Editor’s Note: This article has been updated since it was originally published.
