If your car's battery went dead, would you know how to use booster cables to start it?

Booster cables, widely available for only a few dollars, are used to connect the dead battery of one car to a charged battery in another car.

A set consists of two cables, each with clamps on the ends. Usually one cable will have black handles (and, perhaps, black insulation) and the other red. The colors cut the chances of mixing the cables up when you connect the two batteries.

First determine if both cars are negatively grounded (all American-made cars have a negative ground). That means the battery post marked with a - is grounded. The post marked with a + is the hot post.

Then turn off all the accessories in both cars. Turn your ignition switch off. Let the other car run at a fast idle. The cars should be close enough so the cables can reach, but not touching each other. If you've got a cigarette going, put it out; batteries give off explosive fumes when charging.

Check the vent caps (if your battery has them). Vent holes should be clear so fumes can escape freely.

Clamp one end of the red cable to the + (ungrounded) post of the good battery. Connect the other end of the red cable to the + terminal of the dead battery. Now clamp one end of the black cable to the - terminal (grounded) of the good battery.

It's safer to clamp the other end of the black cable to the engine block of the car with the dead battery rather than to the - post of the dead battery. That way if you've gotten the lines crossed it will do no damage, whereas attaching to the wrong posts could cause the battery to explode.

Now try to start your car. If it doesn't start within 10 seconds, stop cranking and let the cables cool for about half a minute. Then try it again for 10 seconds.

After the car has started, remove the cables in the reverse sequence used to hook them up. Take care not to let the cable clamps touch each other or metal parts as you hook and unhook them.

A final word of caution: Never try to jump-start a battery that is frozen.