Tools and Materials

Tools

Materials

Cleaning Gloves (Optional)
Aluminum Foil (Optional)

Note

Product costs, availability and item numbers may vary online or by market.

Tips for Jump Starting a Car

If your car battery is dead or weak and won’t crank your car, a jump start can be a relatively quick way to get the engine started. We’ll tell you how to use jumper cables to jump-start a battery on a conventional gasoline-powered car below, but here are some tips to review before you begin.

Refer to the Manuals: Vehicle manuals should provide instructions for jump starting that are specific to the car. Always follow the manufacturer’s instructions. You should also verify that the batteries are compatible with the same voltage and grounding — in most cases 12 volts with negative grounds.
Wear Eye Protection: There’s a potential for sparks when jump starting a car and it’s always a good idea to protect your eyes when working with a vehicle battery.
Take Care of Loose Clothing, Hair and Jewelry: Make sure there’s nothing that could get caught in the engine.
Check the Engine Compartment of Both Cars: You’ll need to know where the batteries are to park the cars so the jumper cables will reach. Identify the positive and negative terminals for both batteries as well as the attachment point for the negative cable in the car you’ll be jump starting.
Inspect the Batteries: Don’t attempt to jump-start a car if either battery appears to be damaged, if either of the cases is bulging or if either battery is frozen.
Check Your Cables: Make sure the jumper cables are in good condition with no breaks or cuts in the insulation. Clean the metal contacts as needed.
Don’t Smoke: Sparks or an open flame near a battery have the potential to cause a battery to explode.
Don’t Work In an Enclosed Area: You’ll be running both cars so make sure there’s good ventilation and no risk of carbon monoxide buildup.

Shop Car Chargers & Jump Starters Shop Automotive Maintenance

Tip

It’s a good idea to invest in a car battery jump starter that’s compatible with your battery. These portable devices are typically small enough to keep in your car and let you jump-start it when there isn’t a car with a good battery available.

Jump Starting a Car

These instructions are general steps on how to hook up jumper cables and start a conventional gasoline-powered car with another conventional gasoline-powered car and don't apply to hybrid or electric vehicles. Always follow the jump-starting instructions for your specific vehicle.

Caution

Wear eye protection when cleaning or attempting to jump-start a car battery. You may want to wear cleaning gloves to protect your hands from grease, dirt and any corrosion.

How to Use Jumper Cables to Start a Car

A green car and a gray car parked facing each other with engine hoods up.

You’ll need a car with a good battery parked close to the car with the dead battery. Make sure the cars are in a safe location. You need room to work and the cars should be close enough that the jumper cables will easily reach from one battery to the other. If possible, parking the cars facing each other is often the best option.

Both cars should be in Park (for an automatic transmission) or Neutral (for a manual transmission) with parking/emergency brakes on. Open the hoods on both cars and secure them in place.

Caution

Don’t let the two vehicles touch.

A car battery with a red cap on the positive post and black cable on the negative post.

Identify the positive and negative terminals on the batteries.

Positive terminals or posts should have a + symbol and may have a red cover or red markings on the attached cable.
Negative terminals or posts will have a – symbol and may have a black cover or black markings on the attached cable.

If you can’t locate the terminals or have any doubt about identifying them, check the manual.

Caution

Don’t make a connection between the two terminals on a battery.

If you see evidence of leakage, damage or swelling on either battery, you’ll need to replace the battery. Don’t attempt a jump start.

The red clamp on a jumper cable connected to the positive terminal on a car battery.

You must connect the jumper cables securely and in the correct order. Don’t let the clamps touch each other. Make sure they won’t interfere with any moving parts on the engine.

Start with the red clamps.

First, connect one of the red clamps on the cables to the positive post on the dead battery. If the two cables are paired together, make sure the black clamp doesn’t touch any metal on the car.
Next, connect the other red clamp to the positive post on the good battery.

If there’s dirt or corrosion on the posts, you can try moving the clamp back and forth on a post to create good contact. If you need to clean the posts, put on eye protection and use a wire brush or aluminum foil to scrub any corrosion away before connecting the clamps. Don’t touch the deposits. If there’s evidence of leakage, don’t attempt to jump the battery.

The black clamp on a jumper cable connected to the grounding post on a car engine.

You’ll connect the black clamps next.

Attach the black clamp to the negative post on the good battery. It may be paired with the red clamp or it may be a separate cable.
Finally, attach the other black clamp to the grounding point on the engine with the dead battery. The grounding point shouldn’t be near the battery. Your car manual may indicate a specific grounding post, a bolt or an unpainted metal component.

Check all of the clamps for a secure connection.

Caution

Don’t attach a cable to the negative post on the battery you’re trying to jump.

The tachometer on a car running at idle speed.

First, start the car with the good battery and let the engine run for a couple of minutes.

Then try to crank the engine with the dead battery. If it doesn’t start, you may need to let the booster engine run for up to 10 or 15 minutes.

Good to Know

If your battery doesn’t start after allowing the good battery to power it for about 15 minutes, stop. Further attempts could cause damage. See the What If My Car Won't Jump Start? section below.

Once you’ve successfully started the car, driving it for about 30 minutes should build up a good charge in the battery as long as it's in good shape. However, it’s a good idea to plan to end your drive at home or another safe location, just in case the car doesn’t restart after you turn it off.

If you suspect the battery needs replacement or if the car won’t start again after the battery charges, you’ll likely need to take it to a mechanic or automotive parts store that can test the battery.

Good to Know

You may need to reset some systems in the car you jump-started. Check your manual for details and instructions.

What If My Car Won't Jump-Start?

If you can’t start your car with a jump start or if it stops running after you disconnect the cables, there are several possible reasons. Check that you’ve got a good connection between the clamps and the batteries and grounding point. If the cables or battery posts are dirty or not connected securely, the dead battery may not be getting enough power.

Related Tags:

Tools

How to Jump-Start a Car In 9 Easy Steps

Tools and Materials

Tools

Materials

Tips for Jump Starting a Car

Jump Starting a Car

How to Use Jumper Cables to Start a Car

What If My Car Won't Jump-Start?

Related Tags: