What Order to Put Jumper Cables on a Car Battery

Connect the cables in this order: red clamp to the dead battery’s positive (+), red clamp to the good battery’s positive (+), black clamp to the good battery’s negative (−), and black clamp to an unpainted metal ground on the car with the dead battery. Start the donor vehicle, wait a couple of minutes, start the disabled vehicle, then remove the cables in reverse: black from the ground on the formerly dead car, black from the good battery, red from the good battery, red from the formerly dead battery. This sequence reduces the risk of sparks near the battery and protects electronics.

Safety and Preparation

Before connecting anything, make sure both vehicles use standard 12‑volt systems, are parked with transmissions in Park (automatic) or Neutral (manual), and parking brakes set. Turn off engines and all accessories (lights, HVAC, infotainment). Inspect batteries for cracks, leaks, or swelling; do not jump a damaged or frozen battery. Wear eye protection, keep metal jewelry away, and ensure cable clamps never touch each other.

Correct Connection Order

Use the following step-by-step sequence to connect the jumper cables safely and correctly. This order minimizes the chance of sparks and protects sensitive electronics by placing the last connection away from the battery.

1. Identify the positive (+, usually red) and negative (−, usually black) terminals on both batteries or the designated jump posts.
2. Attach the red clamp to the positive (+) terminal of the dead battery.
3. Attach the other red clamp to the positive (+) terminal of the good (donor) battery.
4. Attach the black clamp to the negative (−) terminal of the good (donor) battery.
5. Attach the remaining black clamp to a clean, unpainted metal point on the engine block or chassis of the car with the dead battery—NOT its negative battery terminal.
6. Ensure cables are routed away from belts, fans, and hot parts, and the clamps are secure.

Following this order reduces ignition risk around the dead battery, where explosive gases may be present, and helps ensure a solid electrical path for the boost.

Starting and Disconnection Order

After the cables are connected, bring the dead battery back to life carefully and remove the cables in the reverse order to avoid arcing and protect components.

1. Start the donor vehicle and let it idle for 2–5 minutes; lightly hold 1,500–2,000 rpm if safe to help charging.
2. Try starting the disabled vehicle. If it doesn’t start, wait another 2–5 minutes and try again. Avoid cranking for more than 10 seconds at a time; allow 30–60 seconds between attempts.
3. Once the disabled vehicle starts, keep both engines running for a minute.
4. Disconnect the cables in reverse order:
   

   1. Remove the black clamp from the grounded metal point on the previously dead car.
   2. Remove the black clamp from the donor battery’s negative (−) terminal.
   3. Remove the red clamp from the donor battery’s positive (+) terminal.
   4. Remove the red clamp from the previously dead battery’s positive (+) terminal.

Reversing the sequence keeps the final disconnection away from the battery, limiting spark risk and preventing accidental short circuits.

Aftercare: What to Do Next

Keep the revived vehicle running for at least 15–30 minutes or drive to allow the alternator to recharge the battery. If the car stalls or needs repeated jumps, have the battery and charging system tested. Many auto parts stores offer free testing. Consider cleaning corroded terminals and checking for parasitic drains if the issue recurs.

Common Mistakes to Avoid

These frequent errors can damage the vehicle or pose safety risks. Review them before you connect cables.

• Clamping the final (black) lead to the dead battery’s negative post—this can spark near battery gases.
• Reversing polarity (mixing up + and −), which can fry fuses and electronics.
• Letting clamps touch each other or metal parts while connected.
• Jump-starting a visibly damaged, frozen, or leaking battery.
• Ignoring vehicle-specific jump points; many cars (especially with trunk/under-seat batteries) provide remote posts under the hood—use them.
• Jumping hybrids/EVs incorrectly. Many have specific 12V procedures—always follow the owner’s manual.
• Using undersized or damaged cables; choose heavy-gauge, well-insulated cables with clean jaws.

Avoiding these mistakes improves safety, prevents costly repairs, and increases the likelihood of a successful jump-start.

Special Cases and Notes

For vehicles with start-stop systems, AGM or lithium 12V batteries, or complex electrical management, consult the owner’s manual for recommended jump points and precautions. Hybrids and EVs often have a conventional 12V battery for accessories; you may jump that system but should never attempt to boost the high-voltage traction battery.

Summary

Connect in this order: red to dead (+), red to donor (+), black to donor (−), black to unpainted metal on the dead car. Start donor, wait, start disabled vehicle, then remove in exact reverse. This method minimizes sparks, protects electronics, and is the widely recommended standard for modern 12V vehicles.