The emergency brake may be located near the gear stick or gas pedal.

Doing this protects both engines from power surges and reduces the risk of electrical shock.

Batteries with similar voltages will be the same size. Still, look for the voltage on the label to avoid possible damage. If you aren’t sure about using a battery, avoid the risk if possible. Try to find a different donor battery or use a rechargeable battery pack.

Check the terminals for corrosion first. It looks like white, green, and blue powder. Clean the terminals by wiping them with a rag or wire brush.

Leads on jumper cables are often made in different lengths to prevent them from touching. If they are the same length, make sure they have not been modified or damaged in any way.

On some vehicles, you may have to remove a plastic cover from the positive battery terminal before you can make this connection. You remove it by twisting it counterclockwise by hand. Connect each clamp 1 at a time. Go slowly in order to avoid mistakes that can damage the vehicles.

Remember to match red to red and positive terminal to positive terminal when applying the red clamps. [9] X Expert Source Duston MaynesAutomotive Repair Specialist Expert Interview. 14 July 2021.

If you attach a clamp incorrectly, stop before you start the cars. Remove the clamps carefully, working 1 at a time to avoid touching them together.

Avoid connecting this clamp to the dead battery unless you have no other choice. This produces a spark that can ignite hydrogen fumes after the car is turned on. Don’t dig too far down to find a metal surface. The fuel lines are down there and you are better off keeping the clamp away from them. Make sure the jumper cable doesn’t hang down into the engine compartment, since it can get caught by the moving parts there.

Depending on the dead battery’s age and condition, it may require more time to charge. Step on the gas pedal to run the RPM up to about 3,000 if you want to drive more power towards the dead battery.

If the car doesn’t start after repeated attempts, your car may have a different problem. It could have a blown fuse. If the car’s lights come on but the engine won’t start, the battery is fine. You may hear the engine make a clicking noise as you try to start it. This could be because of a faulty starter.

Leave the car running so it has time to continue charging or else you will need to jump it again. Be careful when handling the cables. Make sure the clamps do not touch until all of them are removed from the batteries.