Correct Jumper Cable Order: How to Safely Jump-Start a Car

The correct jumper cable order is: connect 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 dead car. To remove, reverse the order: black from the ground on the dead car, black from the good battery, red from the good battery, red from the dead battery. This sequence minimizes sparks and protects sensitive electronics.

Why the Order Matters

Modern vehicles have sensitive electronics and battery management systems. Connecting in the right order reduces the risk of hydrogen gas ignition at the battery, prevents short circuits, and helps avoid voltage spikes that can damage control modules. Using the chassis or designated ground on the dead vehicle for the final connection keeps any arcing away from the battery.

Prepare the Vehicles

Before attaching cables, ensure both vehicles are compatible and set up correctly to avoid damage or injury. The following list outlines the essential pre-connection checks.

1. Verify both systems are 12V automotive electrical systems (do not connect 12V to 24V trucks or specialty systems).
2. Park vehicles so cables reach comfortably, but do not let the vehicles touch.
3. Set parking brakes, shift to Park (automatic) or Neutral (manual), and switch off all accessories (lights, HVAC, infotainment).
4. Inspect batteries for cracks, leaks, or heavy corrosion; do not jump a damaged or frozen battery.
5. Locate the correct jump points; many modern cars require using remote posts under the hood, not the battery terminals.
6. Wear eye protection and remove dangling jewelry; keep flames and smoking materials away.

Completing these checks ensures you’re working with safe equipment and have identified the proper connection points for your specific vehicles.

Connection Order (Using Cables Between Two 12V Vehicles)

Follow this exact connection order to minimize sparks and protect electronics. The steps assume standard negative-ground vehicles, which includes virtually all modern cars.

1. Attach red (positive) clamp to the dead battery’s positive (+) terminal or designated positive jump post.
2. Attach the other red (positive) clamp to the good battery’s positive (+) terminal or positive post.
3. Attach black (negative) clamp to the good battery’s negative (−) terminal or designated negative post.
4. Attach the other black (negative) clamp to a solid, unpainted metal point on the dead car (engine block or chassis ground stud), away from the battery and fuel system.

This sequence keeps the final, potentially sparking connection away from the dead battery, reducing ignition risk from any vented hydrogen gas.

Starting Procedure and Charging Time

Once connected, bring power to the dead battery gradually and avoid cranking continuously, which can overheat cables and starters. Use the following steps.

1. Start the good (donor) vehicle and let it idle for 2–5 minutes to send charge to the dead battery.
2. Gently rev the donor to about 1,500–2,000 rpm for 30–60 seconds if needed (especially in cold weather) to boost alternator output.
3. Attempt to start the dead vehicle. If it doesn’t start, wait another 2–3 minutes and try again.
4. If the dead vehicle still won’t start after 3–4 attempts, stop; further attempts may indicate a deeper issue (battery, starter, fuel, or immobilizer).

Allowing a brief charge period reduces strain on both vehicles and increases the odds of a successful start with minimal risk.

Disconnection Order (Reverse the Sequence)

Remove the cables in the exact reverse order of connection to avoid short circuits and voltage surges.

1. Remove black (negative) clamp from the dead vehicle’s chassis/ground point.
2. Remove black (negative) clamp from the good vehicle’s negative (−) terminal.
3. Remove red (positive) clamp from the good vehicle’s positive (+) terminal.
4. Remove red (positive) clamp from the formerly dead vehicle’s positive (+) terminal.

Reversing the sequence ensures the positive leads are never left energized without a safe return path, reducing the chance of sparks or accidental shorts.

After the Jump

Once the dead vehicle is running, take steps to stabilize its electrical system and confirm the battery’s condition.

1. Keep the engine running for at least 20–30 minutes of driving; idling charges slowly and may not fully recover the battery.
2. Avoid high electrical loads (rear defrost, heated seats) for the first few minutes.
3. If the vehicle stalls or struggles to crank again shortly after, have the battery and charging system tested.

These actions help replenish the battery and identify whether the underlying issue is a weak battery or a failing alternator/charging system.

Safety Tips and Common Pitfalls

The following reminders help prevent injuries and damage during a jump-start.

• Never let red and black clamps touch together or contact the same metal surface.
• Match polarities exactly: red to (+), black to (−). Reversed polarity can destroy electronics instantly.
• Use the designated ground point on vehicles with battery sensors or start-stop systems; avoid clamping directly to the negative battery post if the manual advises against it.
• Do not attempt to jump a visibly damaged, swollen, frozen, or leaking battery.
• Avoid jump-starting across different system voltages (12V vs. 24V); consult labels on batteries and under-hood decals.
• Keep cables clear of belts, fans, and hot exhaust components.

Adhering to these precautions significantly lowers the chance of accidents and costly electrical damage.

Special Cases: Hybrids, EVs, and Portable Jump Starters

Hybrids

Hybrids use a conventional 12V battery to power electronics and relays. You can often jump-start the 12V system, but always use the manufacturer’s designated jump posts and procedure—never attempt to access or jump the high-voltage battery.

Electric Vehicles (EVs)

Most EVs have a 12V battery that can be boosted to wake the vehicle, but consult the manual; many manufacturers recommend using a portable jump pack and advise against using an EV to jump another vehicle. Never connect to high-voltage components.

Portable Jump Starters

Follow the same clamp order (red to (+), black to chassis ground), then power on the pack as directed. Many packs have reverse-polarity and spark protection, but correct order and secure connections remain critical.

Troubleshooting If the Car Won’t Start

If the engine still fails to crank or start, the checklist below can help isolate the cause.

• No crank, no click: Possible loose connections, blown main fuse, or dead starter/relay.
• Rapid clicking: Very low battery or poor cable connection; clean and tighten clamps and try again.
• Cranks but won’t start: Could be fuel, ignition, immobilizer, or sensor issue; not just the battery.
• Stalls after starting: Alternator/charging fault or severe battery failure; have the system tested.

These symptoms guide whether to retry the jump, secure better connections, or seek professional diagnosis.

Memory Aid

To remember the order quickly, this mnemonic can help.

• Connect: Dead red (+), Donor red (+), Donor black (−), Dead ground (metal).
• Disconnect: Dead ground, Donor black, Donor red, Dead red.

This sequence emphasizes placing the final connection away from the dead battery and reversing the steps to disconnect.

Summary

Correct jumper cable order: red to dead (+), red to good (+), black to good (−), black to unpainted metal on dead; then remove in reverse. Use designated jump points, keep sparks away from the battery, and confirm both vehicles are 12V systems. If the vehicle won’t start after several attempts or stalls soon after, have the battery and charging system tested.

Is there an order for putting on jumper cables?

Make sure you have followed these steps in proper order: red clip from booster cable to positive terminals, then black clip from booster cable to negative terminals. Once all connections are made, start up your working vehicle and let it run for a few minutes before attempting to start your dead battery’s engine.

Do I connect black or red first?

When connecting jumper cables to a car with a dead battery, always connect the red/positive cable first to the positive (+) terminal of the dead battery, and then to the positive terminal of the working battery. The negative (black) cables should be connected last, with one to the negative terminal of the working battery and the other to an unpainted metal surface on the dead car’s engine block or frame to complete the circuit.
 
This video demonstrates how to safely connect jumper cables to a car battery: 51sStan CravensYouTube · Oct 9, 2018
Step-by-Step Guide to Connecting Jumper Cables:

1. Turn off both vehicles: Opens in new tabEnsure the ignition keys are in the off position in both the car with the dead battery and the donor car. 
2. Connect the red (positive) cable to the dead battery: Opens in new tabAttach one red clamp to the positive (+) terminal of the dead battery. 
3. Connect the red (positive) cable to the donor battery: Opens in new tabAttach the other red clamp to the positive (+) terminal of the good battery on the donor vehicle. 
4. Connect the black (negative) cable to the donor battery: Opens in new tabAttach one black clamp to the negative (-) terminal of the donor vehicle’s good battery. 
5. Connect the black (negative) cable to the dead car’s frame: Opens in new tabAttach the final black clamp to an unpainted, unmoving metal part of the engine block or frame of the car with the dead battery. A slight spark may occur, which is normal. 

Why this order?

• Red first: Connecting the positive (red) cable to both batteries first creates a complete circuit without completing the negative side. 
• Last connection to metal: The last black clamp is attached to an unpainted metal surface on the dead car’s frame, not the negative terminal. This minimizes the risk of sparks, as the battery releases hydrogen gas that could cause an explosion. 

What is the correct order of jumper cables?

To connect jumper cables correctly, attach the red (positive) clamps to the positive terminals of both batteries (dead first, then good), then attach the black (negative) clamps to the negative terminal of the good battery and an unpainted metal component (a “ground”) on the dead car. Remove them in the reverse order: first, the black clamp from the metal ground, then the black clamp from the good battery’s negative terminal, followed by the red clamps. 
Connecting the Cables

1. Red to Dead Battery (+): Opens in new tabConnect the first red clamp to the positive (+) terminal of the dead battery. 
2. Red to Good Battery (+): Opens in new tabConnect the other red clamp to the positive (+) terminal of the good battery in the working vehicle. 
3. Black to Good Battery (-): Opens in new tabConnect the first black clamp to the negative (-) terminal of the good battery. 
4. Black to Metal Ground: Opens in new tabConnect the final black clamp to an unpainted, non-moving metal component on the engine block or chassis of the vehicle with the dead battery. This avoids sparks near the battery, which can be a fire hazard due to gases it may release. 

This video demonstrates the entire process of connecting jumper cables, including the final grounding step: 56sLes SchwabYouTube · May 23, 2017
Starting the Vehicles

1. Start the Working Vehicle: Start the car with the good battery and let it run for several minutes to allow the battery to charge. 
2. Start the Stalled Vehicle: Attempt to start the car with the dead battery. 
3. Allow for Charging: If the car starts, let both vehicles run for at least 30 minutes to allow the alternator to fully charge the battery. 

Disconnecting the Cables (Reverse Order) 

1. Black from Metal Ground: Disconnect the black clamp from the unpainted metal component on the dead car. 
2. Black from Good Battery (-): Disconnect the black clamp from the negative terminal of the good battery. 
3. Red from Good Battery (+): Disconnect the red clamp from the positive terminal of the good battery. 
4. Red from Dead Battery (+): Disconnect the red clamp from the positive terminal of the dead battery. 

What is the correct order to take off jumper cables?

To remove jumper cables safely, disconnect them in the reverse order of connection: first the negative (black) clamp from the dead car, then the negative (black) clamp from the good car, followed by the positive (red) clamp from the good car, and finally the positive (red) clamp from the dead car. This sequence prevents sparks and potential damage to your vehicles’ electrical systems.
 
This video demonstrates the entire process of jump-starting a car, including how to disconnect the jumper cables: 1mAmericas Drivers EdYouTube · Mar 31, 2016
Here are the steps for removing jumper cables safely:

1. Turn off both engines: to ensure no electrical current is flowing. 
2. Disconnect the black (negative) clamp: from the grounded metal on the car with the dead battery. 
3. Disconnect the black (negative) clamp: from the negative terminal of the good (jumping) car’s battery. 
4. Disconnect the red (positive) clamp: from the positive terminal of the good (jumping) car’s battery. 
5. Disconnect the red (positive) clamp: from the positive terminal of the formerly stalled car’s battery. 

Important Safety Tips:

• Maintain distance: Keep at least two feet of distance between the vehicles while disconnecting the cables to prevent accidental contact. 
• Avoid sparks: Removing the negative cables first helps to prevent a short circuit, which can cause sparks and potentially damage electrical components or even the battery. 
• Clip them together: When not connected to a terminal, it’s a good idea to clip the red and black ends of the cables together to keep them separated and avoid accidental contact.