How to Jump-Start a Car Safely
The car just clicks, or won't do anything at all. With jumper cables and a second car, you can be on your way in 10 minutes. The order of the clamps matters, so follow it exactly.
Check your car's manual first
Some cars have special jump-start points under the bonnet instead of using the battery directly, and hybrids and electric cars have their own instructions. A quick look at the manual's “jump starting” section avoids expensive mistakes. Never jump a battery that's cracked, leaking or frozen.
HOWJump-start the car
Follow the steps in exact order.
- Park the working car close, nose to nose or side by side, without the cars touching.
- Turn off both engines, put them in Park (or neutral with the handbrake on), and switch off lights, radio and fans.
- Open both bonnets and find the batteries. + (positive) is usually red; – (negative) is usually black.
- Red clamp to + on the dead battery.
- Other red clamp to + on the good battery.
- Black clamp to – on the good battery.
- Last black clamp to bare, unpainted metal on the dead car's engine or frame, away from the battery. Not the dead battery's negative.
- Start the working car and let it run for 2–3 minutes.
- Try starting the dead car. If it doesn't start, wait a few more minutes and try again. Don't crank for more than about 10 seconds at a time.
- Black clamp from the bare metal on the jumped car.
- Black clamp from the good battery.
- Red clamp from the good battery.
- Red clamp from the jumped battery.
Drive for at least 20–30 minutes, ideally not in stop-start traffic, so the alternator can recharge the battery. If the car won't start again later, the battery may need replacing; most auto parts stores test batteries for free.
If it clicks but won't crank after several minutes, the problem may be the battery, starter or connections. Call your roadside assistance service.
FAQCommon questions
What if I don't have another car?
A portable jump starter (a rechargeable battery pack with clamps) works on your own. Or call roadside assistance.
Why connect the last clamp to bare metal, not the battery?
Batteries can release flammable gas, and the last connection can spark. Making it away from the battery is safer.
How do I know if I need a new battery?
If it keeps going flat, struggles to start in the cold, or is more than about 3–5 years old. Auto parts stores can test it, often free.
Can I jump-start an electric car or hybrid?
They have a small 12-volt battery that can go flat, but the procedure varies. Follow the owner's manual, or call roadside assistance.