Jump-start a car

Move out of traffic if you can, switch on your hazard lights, and apply the parking brake. Read the full checklist before connecting anything. Only jump-start a vehicle with a compatible 12-volt system. Check both owner manuals if you are unsure. Keep metal jewelry, loose clothing, and hands away from moving parts. Never smoke or create sparks near a battery. Stop if a battery is cracked, leaking, swollen, frozen, or hot. Arrange professional help instead. Driving an EV? Do not use this ICE jump-start procedure on a high-voltage EV battery. Follow your vehicle manual for its 12-volt system, or call roadside assistance; never connect cables to orange high-voltage components.

Jumper cables in good condition, or a charged 12-volt jump starter. A donor vehicle with a matching 12-volt system (if using cables). Safety glasses and gloves if available. Your vehicle manual, especially for battery location and designated jump points.

Position the vehicles Park close enough for the cables to reach, but do not let the vehicles touch. Put both vehicles in Park or Neutral, apply the parking brakes, and turn both ignitions off. Find the terminals Open the hoods and identify the positive (+) and negative (−) terminals or marked jump points. If using a jump starter, keep it switched off for now. Connect red to the dead battery Attach one red clamp to the stalled vehicle’s positive (+) terminal. Make sure the clamp is secure and cannot touch metal. Connect red to the donor Attach the other red clamp to the donor battery’s positive (+) terminal. Connect black safely Attach one black clamp to the donor battery’s negative (−) terminal. Attach the final black clamp to an unpainted, solid metal ground point on the stalled vehicle, away from its battery and moving parts. Start and wait Start the donor vehicle and let it run for a few minutes. Then try to start the stalled vehicle for no more than about 10 seconds at a time. Pause between attempts. Remove the cables in reverse Once the stalled vehicle starts, switch off the jump starter if used. Remove the black clamp from the stalled vehicle, then donor black, donor red, and stalled-vehicle red. Keep clamps from touching each other. Let the car recharge Keep the revived vehicle running or drive it as the manual recommends. If it stalls again or will not start after a couple of attempts, stop and call a professional.

Connecting positive and negative terminals in the wrong order or reversing polarity. Clamping the final negative connection directly to the stalled battery when the manual specifies a remote ground point. Letting the clamps touch each other or a moving belt, fan, or hot engine part. Cranking repeatedly for a long time instead of pausing between short attempts. Assuming a jump-start fixes a battery that is damaged, leaking, or unable to hold a charge.

The battery is cracked, leaking, swollen, frozen, or smells strongly of sulfur. The vehicle is an EV or hybrid and you cannot confirm the correct 12-volt procedure in its manual. The car does not start after two or three careful attempts, or the cables become hot or spark heavily. You are stopped in an unsafe location, cannot identify the terminals, or feel unsure at any point.