Updated · Batteries
Before you connect anything
A minute of prep prevents most problems. Batteries can release hydrogen gas, which is why the last connection goes away from the battery.
- Park somewhere safe and off the road, both cars in Park or neutral with the parking brake set
- Turn off both engines, the lights and all accessories
- Look at the dead battery: don't jump one that is cracked, leaking, swollen or frozen
- Find the positive (+, usually red) and negative (−, black) posts; some cars have jump points under the hood instead
- Wear eye protection if you have it, and keep flames and cigarettes away
Connect the cables in this order
Keep the clamps from touching each other or any other metal while you work.
- Red clamp to the positive post of the dead battery
- Other red clamp to the positive post of the good battery
- Black clamp to the negative post of the good battery
- Last black clamp to bare, unpainted metal on the dead car's engine, or the ground point the manual shows, away from the battery
Start the engines
Start the donor car and let it run for a few minutes. Then try the dead car. If it doesn't start, wait a few more minutes before the next try, and keep each try short, around 10 seconds.
Once it starts, remove the cables in reverse order: the ground clamp first, then the black clamp on the good battery, then the reds. Keep the revived car running and drive it for at least 20 to 30 minutes so the alternator can recharge the battery.
When not to do it yourself
Some situations call for a technician, not a pair of cables. Many carmakers, for example, advise against using a hybrid or electric car as the donor. Don't do it yourself when:
- The battery is cracked, bulging, leaking or smells like rotten eggs
- You're stopped on a highway shoulder next to moving traffic
- The cables are thin or frayed, or the clamps are loose
- Either car is a hybrid or EV and its manual warns against jumping it that way
If it still won't start
Clicking with good cables usually means the battery is too far gone or a connection is bad. No sound at all can point to the starter, a fuse or the ignition. If the car starts but dies again soon after, the alternator may not be charging.
We handle jump starts 24/7 across Dallas–Fort Worth with proper equipment, and if the battery won't hold a charge, we can replace it on the spot.