How to jump-start a car (and why heat kills batteries)

To jump-start a car, connect red to the dead battery's positive (+) post, red to the good battery's positive, black to the good battery's negative (-), and the last black clamp to bare, unpainted metal on the dead car, away from the battery. Start the good car, wait a few minutes, then start the dead one. Arizona heat wears out car batteries faster than cooler climates do, so a battery that dies in summer is often just old.

Time: about 15 minutes. Skill: easy, but follow the order exactly.

Safety first

• Read your owner's manual. Some cars, including hybrids and electric vehicles, have special jump points or rules.
• Do not jump a battery that is cracked, leaking, bulging or has a strong rotten-egg smell. Call for help.
• Wear gloves and eye protection if you have them. Batteries can release gas, so no smoking, no flames and no sparks.
• Make sure both cars are off, in Park or Neutral, with the parking brakes on and keys out of the ignition.
• Keep the clamps from touching each other once they are attached to a battery.
• Use cables in good shape. Frayed cables are a hazard.

How do you jump-start a car?

1. Park the cars close enough for the cables to reach, but not touching. Turn both off.
2. Open both hoods and find the batteries. Positive is usually marked + and has a red cover. Negative is marked -.
3. Clamp red to the dead battery's positive (+) post.
4. Clamp the other red end to the good battery's positive (+) post.
5. Clamp black to the good battery's negative (-) post.
6. Clamp the other black end to bare metal on the dead car, such as an engine bracket or a bolt, away from the battery and moving parts. This is your ground. A little spark here is normal, and it is why you keep it away from the battery.
7. Start the good car and let it run for a few minutes.
8. Try starting the dead car. If it does not start, wait a few more minutes and try again. If it still will not start after a couple of tries, stop. The problem is more than a dead battery.
9. Remove the cables in reverse order: black from the ground, black from the good battery, red from the good battery, red from the dead battery.
10. Drive the car for at least 20 to 30 minutes, or longer, to recharge. Do not shut it off right away.

Why does Arizona heat kill car batteries?

Heat speeds up the chemical wear inside a battery and can dry out the liquid in it. Under a hood in a Valley summer, that is a lot of stress. The battery may seem fine and then fail on a cooler morning, because the heat damage was already done. Many batteries in hot climates wear out sooner than in cooler ones. If yours is three or four years old, have it tested.

Signs of a weakening battery include a slow crank, dim lights at idle, a clicking sound, corrosion on the terminals and a battery warning light.

How do you make a battery last?

• Park in shade or a garage when you can.
• Keep the terminals clean. White or blue crust means corrosion; a shop can clean it.
• Ask for a free battery test during an oil change.
• Drive longer trips sometimes. Short hops do not fully recharge a battery.

When to call a pro

Call a pro if the car will not start after a jump, dies again soon after, or if you see a swollen or leaking battery. You may need a new battery or an alternator check. Here are local auto repair shops in the directory, with phone numbers:

If you are stranded, call roadside assistance or ask the helper to find a business near you, or browse Phoenix businesses.

Questions people ask

How long should I drive after a jump start?

Drive for at least 20 to 30 minutes so the alternator can recharge the battery. If the car will not restart afterward, the battery or alternator likely needs to be tested.

Can you jump-start a car in the rain?

Rain does not make it impossible, but take extra care. Keep the clamps and connections as dry as you can, and do not do it if there is lightning nearby. If you are not comfortable, call a pro.

How long do car batteries last in Arizona?

Many wear out sooner than in cooler places. Have yours tested once a year after it is a few years old, so you are not stuck in a hot parking lot.

See every auto repair shop in Phoenix