What order should you jump‑start a car?

Connect the cables in this order: red to the dead battery’s positive (+), red to the donor battery’s positive (+), black to the donor battery’s negative (−), and black to an unpainted metal ground on the dead car. Start the donor, wait a minute or two, then start the dead car. Remove cables in reverse: black from ground, black from donor, red from donor, red from dead. This sequence minimizes sparks near the battery and protects sensitive electronics; details and exceptions follow.

Safety and preparation

Before you hook anything up, confirm you’re working with compatible 12‑volt systems, identify the correct terminals, and reduce fire or shock risks. Many modern cars provide dedicated jump posts under the hood—use them if available rather than clamping directly to the battery, especially if the battery is remote (trunk/under-seat) or has an intelligent battery sensor on the negative terminal.

• Tools: Quality jumper cables (4–6 gauge, 12–20 ft) or a portable jump starter; safety glasses and gloves.
• Verify: Both vehicles are 12 V systems; polarity on both batteries; no cracks, leaks, or frozen battery (do not jump a frozen or leaking battery).
• Position: Park nose‑to‑nose without touching, engage park/neutral and parking brakes, switch off accessories, and open hoods.
• Locate: Positive (+, usually red) and negative (−, usually black) terminals or manufacturer‑marked jump posts. Avoid clamping onto a negative terminal if it has an Intelligent Battery Sensor—use the recommended body ground point.
• Check manuals: Some vehicles (EVs, hybrids, start‑stop systems) have specific procedures and designated posts.

Taking a minute to stage the cars, identify posts, and don safety gear prevents most mishaps and protects electronic modules.

The correct connection order

Use this step‑by‑step sequence to connect the cables. It reduces the chance of sparking near the battery where flammable gases may be present.

1. Attach red clamp to the dead car’s positive (+) post or positive jump post.
2. Attach red clamp to the donor car’s positive (+) post.
3. Attach black clamp to the donor car’s negative (−) post.
4. Attach the final black clamp to a solid, unpainted metal ground on the dead car (strut tower bolt, engine block ground, or designated ground post)—not the dead battery’s negative terminal.

If your vehicle has a labeled ground or jump post, use it. Keeping the final connection away from the battery reduces explosion risk and avoids confusing an intelligent battery sensor.

Starting sequence and timing

With the cables connected, bring the donor system online and give the dead battery a brief surface charge before cranking. Avoid extended cranking that can overheat starters and cables.

1. Start the donor car and let it idle 1–3 minutes; gently hold 1,500–2,000 rpm to help charging.
2. Try starting the dead car for up to 10 seconds. If it doesn’t catch, wait 30–60 seconds and try again.
3. If still no start after 3 attempts, reassess: connections, ground point, or battery condition. Consider a charger or jump pack “boost” function if available.

Brief charging stabilizes voltage, improving the chance of a clean start without straining either vehicle’s electrical system.

Disconnecting: the reverse order

Once the dead vehicle is running, remove the cables in the exact reverse sequence to avoid arcing and accidental shorts.

1. Remove the black clamp from the dead car’s ground point.
2. Remove the black clamp from the donor car’s negative (−) post.
3. Remove the red clamp from the donor car’s positive (+) post.
4. Remove the red clamp from the previously dead car’s positive (+) post.

Keep the metal ends of the clamps from touching each other or any metal parts as you remove them to prevent sparks.

After the jump: what to do next

Getting the car started is only part of the job; now you need to recover the battery and confirm the charging system is healthy.

• Let the engine run for at least 20–30 minutes or drive to allow the alternator to replenish charge; highway driving is better than idling.
• A deeply discharged battery should be recharged fully with a smart charger (AGM/EFB‑compatible for start‑stop cars) to avoid alternator overload.
• Test the system: With the engine running, voltage at the battery should read roughly 13.8–14.7 V (consult spec). Lower may indicate charging issues; higher may signal regulator trouble.
• Have the battery load‑tested if it’s more than 3–4 years old or has been repeatedly discharged.

Proper recovery extends battery life and reduces the chance you’ll need another jump soon.

Special cases and cautions

Some vehicles and tools have variations on the standard procedure. When in doubt, follow the owner’s manual for the vehicle or device you’re using.

• Portable jump starters: Many packs require clamping to the dead battery’s own + and − terminals so the pack’s safety electronics can work; follow the pack’s instructions. Turn the pack off before connecting, then power it on.
• Hybrids and EVs: Never attempt to jump the high‑voltage traction battery. You may jump or be jumped via the 12 V system using the manufacturer’s specified posts. Some EVs can provide a 12 V jump to another car only if the manual permits it.
• Start‑stop/AGM/EFB batteries: Use correct posts and a compatible charger for recovery. Avoid clamping to the IBS (intelligent battery sensor) ring on the negative terminal; use the designated ground point.
• 24 V systems (many trucks, RVs, heavy equipment): Do not mix with 12 V cars. Use the correct voltage source and procedure.
• Frozen or damaged batteries: If the case is swollen, cracked, leaking, or the battery may be frozen (common below −10°C/14°F), do not jump—replace or thaw and test first.
• Safety basics: No smoking or open flames near batteries; remove loose jewelry; keep clamps from touching; verify polarity twice.

Following these exceptions prevents expensive damage to power electronics and reduces personal risk.

Troubleshooting if it still won’t start

If the engine refuses to crank or start after correct connections and several attempts, look for these common issues before replacing parts.

• Poor connections: Corrosion, paint under the ground clamp, or loose clamps—clean and reclamp.
• Completely failed battery: Some batteries won’t accept a jump; try a dedicated charger or replacement.
• Security/immobilizer or key fob issues: Low fob battery or alarm lockout can mimic a dead battery.
• Starter/solenoid or fuse failure: Clicking without crank often points to these components.
• Fuel/ignition faults: Cranks but won’t start may be unrelated to the battery (e.g., fuel pump, crank sensor).

Systematic checks can quickly separate a simple battery problem from a deeper electrical or mechanical fault.

Summary

Connect in this order—red to dead +, red to donor +, black to donor −, black to a ground on the dead car—then start the donor, start the dead car, and disconnect in reverse. Use designated jump posts when provided, avoid sparks near the battery, and fully recharge and test the battery afterward. Adjust for special cases like portable jump packs, hybrids/EVs, and AGM/start‑stop systems by following the specific manual instructions.

What is the correct order to jump start a car?

To jump a car battery, connect jumper cables by first attaching the red clamp to the dead battery’s positive (+) terminal, then the other red clamp to the working car’s positive terminal. Next, connect the black clamp to the working car’s negative (-) terminal and the final black clamp to an unpainted metal surface on the dead car, away from the battery. After connecting both cars, start the working vehicle to charge the dead battery, then try to start the dead car.
 
This video demonstrates the complete process of jump-starting a car, including safety precautions: 50sCars.comYouTube · Oct 11, 2024
Step-by-Step Connection Guide:

1. Position the vehicles: Park the working car close to the dead car, but ensure they do not touch. 
2. Turn off both cars: Make sure both vehicles are completely off before connecting anything. 
3. Locate battery terminals: Identify the positive (+) and negative (-) terminals on each battery. 
4. Connect the red (positive) cables: 
   • Attach one red clamp to the dead battery’s positive (+) terminal. 
   • Attach the other red clamp to the working battery’s positive (+) terminal. 
5. Connect the black (negative) cables: 
   • Attach one black clamp to the working battery’s negative (-) terminal. 
   • Attach the final black clamp to an unpainted, unmoving metal part of the dead car (like the engine block). This helps prevent sparks near the battery. 
6. Start the working car: Let the working car run for a few minutes to begin charging the dead battery. 
7. Start the dead car: Attempt to start the dead car. 
8. Disconnect the cables: Once the dead car starts, disconnect the jumper cables in the reverse order: black negative clamp from the dead car’s metal surface, then the black negative clamp from the working car, then the red positive clamp from the working car, and finally the red positive clamp from the dead battery. 

This video shows the step-by-step process of disconnecting the cables after a successful jump-start: 58sAAA Connect Video Hub | Auto Club GroupYouTube · Sep 23, 2024
Why the Order Matters:
The correct order is crucial for safety. Connecting the last negative clamp to a grounded metal surface helps prevent sparks, which can be a fire or explosion hazard with lead-acid batteries, especially if they are venting hydrogen gas. 
After the Jump:
Let the jump-started car run for at least 15-20 minutes to allow the alternator to fully charge the battery.

What is the correct jumper cable order?

Jump-starting a car safely and effectively requires following a 6-step process: Positioning the booster vehicle, securely connecting the jumper cables in the correct order (positive to dead battery, positive to booster, negative to booster, then negative to grounded metal), starting the booster vehicle, and …

Which car do I start first when jumping a car?

When jump-starting a car, the first terminal to connect is the red (+) positive terminal on the dead battery. You then connect the other red (+) clamp to the positive terminal of the working car’s battery. Next, you attach the black (-) clamp to the negative terminal of the working car’s battery. Finally, you attach the last black (-) clamp to an unpainted, unmoving metal part of the dead car’s engine or frame, away from the battery. 
Step-by-step instructions for connecting jumper cables:

1. Position the cars: Ensure the working and dead vehicles are close enough for the cables to reach but not touching. 
2. Turn off both cars: Make sure both vehicles’ engines are off and keys are out of the ignition. 
3. Attach the red (+) clamps: Connect one red clamp to the positive (+) terminal of the dead battery. Then, connect the other red clamp to the positive (+) terminal of the good battery. 
4. Attach the black (-) clamps: Connect one black clamp to the negative (-) terminal of the good battery. 
5. Connect to ground: Connect the final black clamp to a clean, unpainted metal surface on the engine or frame of the dead car, away from the battery. This is a crucial safety step to prevent potential sparks that could ignite gases from the battery. 
6. Start the working car: Start the engine of the car with the good battery and let it run for a minute or two to allow the dead battery to begin charging. 
7. Start the dead car: Once the working car has been running, try to start the car with the dead battery. 

Remember to follow these steps carefully to ensure a safe and effective jump-start.

What are the 5 steps to jumpstart a car?

How to Use Jumper Cables to Start a Car

1. Step 1: Park the Cars Safely.
2. Step 2: Turn Both Cars Off.
3. Step 3: Find the Battery Terminals.
4. Step 4: Connect the Red Jumper Cable Clamps.
5. Step 5: Connect the Black Jumper Cable Clamps.
6. Step 6: Jump-Start the Car.
7. Step 7: Disconnect the Black Cable Clamps.