How to Hook up Jumper Cables?

Your car battery could be too weak to start your car for a number of reasons: faulty alternator, leaving the lights on,

cold weather or simply an older battery that no longer holds sufficient charge.

Whatever the cause, you can use jumper cables to connect your dead battery to a live vehicle battery of the same size.

The live battery then charges your dead battery enough to get the car started again.

Step 1

Park the donor vehicle (live battery) next to the vehicle with the dead battery. Position the vehicles

so that the batteries are as close together as possible, but make sure the 2 cars do not touch. 

Step 2

Switch the radio, headlights, interior lights, and--if safe--emergency flashers--off on both vehicles.

Step 3

Turn both vehicles off. Set the parking brakes, and switch each car into park or neutral (for automatic or manual transmissions, respectively). 

Step 4

Identify the positive and negative battery terminals. The cables leading to the positive battery terminal are almost always red.

If you're in doubt, the battery itself has a "+" and "-" sign to mark the positive and negative terminals. 

Step 5

Separate the jumper cable clamps so that there's no risk of them accidentally touching together--this could cause a short circuit.

Step 6

Clamp one of the red clamps securely onto the positive terminal of the dead battery. Make sure the clamp is securely attached to the battery terminal.

On some vehicles, you may have to remove a plastic cover from the positive battery terminal before you can make this connection.

Step 7

Secure the other red clamp to the positive terminal on the donor battery.

Again, make sure the clamp is securely connected and won't slip off due to vibration in the engine compartment. 

Step 8

Connect one of the black jumper-cable clamps to the negative terminal on the donor battery.

Step 9

Attach the other black clamp to an unpainted metal surface inside the engine compartment on the vehicle with the dead battery--the farther from the battery, the better.

• An unpainted bolt on the engine block is ideal. Remember, the clamp must be able to "bite" securely onto the object in question and hold in place, even if the engine vibrates.
• You can, theoretically, connect the second black clamp to the negative terminal on the dead battery instead. But this produces a spark, which could ignite hydrogen fumes from the battery.
• Check to make sure no part of the jumper cables--or tools, or battery covers--dangle into the engine compartment, where it might foul belts, pulleys or other moving parts.

Step 10

Start the donor vehicle and let it idle for a few minutes before you attempt to start the car with the dead battery.

Run the RPM up to about 3,000 as you attempt to start the car with the dead battery.

Step 11

Disconnect the jumper cables in the following order once you get the dead-battery car running:

• Negative ground (engine-block bolt or, less desirably, negative terminal on the dead battery).
• Negative terminal (black clamp) on the donor battery.
• Positive terminal on the donor battery.
• Positive terminal on the previously dead battery.