How to Use Jumper Cables Safely and Correctly

Connect the red clamp to the dead battery’s positive terminal, the other red clamp to the donor battery’s positive, the black clamp to the donor’s negative, and the final black clamp to a bare metal ground on the dead vehicle; start the donor, then start the dead vehicle, and disconnect in reverse order. In practice, correct jumper-cable use also means confirming both vehicles’ 12-volt systems, parking safely, using designated jump posts when provided (common on modern cars), and taking precautions to avoid sparks and battery damage.

Prepare the Vehicles and Put Safety First

Before attaching any cables, ensure both vehicles and bystanders are safe. Modern vehicles often have battery management sensors and remote jump posts, and hybrids/EVs follow specific rules, so a quick check of the owner’s manual is wise.

The items below outline essential safety checks and setup steps to minimize risk and protect vehicle electronics.

• Confirm both vehicles use 12-volt electrical systems; never mix 12V and 24V systems.
• Park vehicles close but not touching, shifters in Park (or Neutral for manual), and set parking brakes.
• Switch off ignitions and all accessories (lights, HVAC, infotainment) on both cars.
• Inspect the dead battery for cracks, leaks, or severe swelling; do not jump a damaged or frozen battery.
• Identify the positive (+, often red cover) and negative (–) points. On many newer cars, use the marked jump-start posts rather than the battery terminals.
• Wear eye protection and gloves if available; keep cables clear of belts, fans, and hot components.

Completing these checks reduces the chance of sparks, protects sensitive electronics, and ensures you use the correct connection points for your vehicle.

Step-by-Step Connection Sequence

The following sequence limits sparking near the battery and protects vehicle electrical systems. Follow the order precisely and avoid clamp-to-clamp contact once connected.

1. With both ignitions off, attach one red clamp to the dead vehicle’s positive (+) terminal or designated positive jump post.
2. Attach the other red clamp to the donor vehicle’s positive (+) terminal or positive jump post.
3. Attach one black clamp to the donor vehicle’s negative (–) battery terminal or negative jump post.
4. Attach the final black clamp to a clean, unpainted metal point on the dead vehicle (engine block, chassis ground stud, or designated negative post)—not directly to the dead battery’s negative terminal, especially on cars with battery sensors.
5. Ensure cables are secure and away from moving parts.
6. Start the donor vehicle and let it idle 2–5 minutes; on a very weak battery, wait longer.
7. Attempt to start the dead vehicle. If it cranks slowly, let the donor idle a bit more and try again. A light press on the donor’s accelerator to hold 1,200–1,500 rpm can help.
8. Once the dead vehicle starts, let both vehicles idle connected for 2–3 minutes to stabilize voltage.
9. Disconnect in reverse order: remove the black clamp from the dead vehicle’s ground, black from the donor negative, red from the donor positive, then red from the revived vehicle positive.
10. Keep the revived engine running at least 20–30 minutes or drive to recharge; then have the battery and charging system tested.

This connection order moves any potential spark away from the battery and ensures a controlled transfer of power. Disconnecting in reverse prevents accidental short circuits.

Aftercare: What to Do Once You’re Running

Getting the engine started is only part of the solution; the next steps help restore charge and identify underlying issues.

• Drive for 20–30 minutes to replenish the battery; idling alone is less effective than steady driving.
• Schedule a battery and alternator test the same day—repeated jump starts often signal a failing battery or charging problem.
• If you frequently make short trips, consider a smart battery maintainer to keep the battery healthy.
• Reset clocks, radios, and driver-assist settings that may have lost power.

Proper aftercare prevents recurring no-starts and helps catch weak batteries or alternators before they strand you again.

Troubleshooting When It Won’t Start

If the engine doesn’t crank or keeps dying, the checklist below can help isolate the problem before you call for service.

• Recheck clamps for solid metal-to-metal contact and correct polarity (+ to +, – to ground).
• Let the donor run longer; extremely discharged batteries may need 5–10 minutes of donor charging before cranking.
• Look for corrosion on terminals; wiggling clamps or lightly brushing corrosion can improve contact (wear eye protection).
• Watch for clicking but no crank—likely a very weak battery or poor connection; silence may indicate a deeper electrical fault or blown fuse.
• If cables or clamps get hot, stop and reassess; overheating suggests high resistance or a short.
• If multiple attempts fail, consider a portable jump starter or professional assistance; the battery may be dead, damaged, or the vehicle may have a starter/immobilizer issue.

Systematic checks can restore a borderline battery, but persistent failure points to a battery past its service life or a charging/starting system fault.

Special Notes for Hybrids, EVs, and Start-Stop Vehicles

Modern vehicles often use battery management systems and remote jump terminals. Hybrids and EVs have separate high-voltage systems; the jump procedure only concerns the 12-volt system.

• Use only the manufacturer’s labeled jump points. Many vehicles with battery sensors advise against clamping to the negative post.
• Hybrids: jump the 12V system using the under-hood posts; never connect to the high-voltage battery.
• EVs: many makers discourage using an EV as a donor; use a portable jump pack or a conventional donor vehicle instead—check the owner’s manual.
• Start-stop/AGM/EFB batteries: procedure is the same, but connecting to designated ground points helps protect battery monitoring sensors.

Following manufacturer guidance for specialized systems protects expensive electronics and avoids warranty concerns.

Choosing the Right Jumper Cables (or a Jump Pack)

Quality gear makes the process safer and more reliable, especially in cold weather or with larger engines.

• Gauge: thicker cables (lower number) work better; 4-gauge is a good all-around choice; 2-gauge for trucks/large engines.
• Length: 12–20 feet offers flexibility without too much voltage drop; ensure robust, copper-clad or pure copper clamps.
• Insulation: heavy, flexible insulation improves durability in cold conditions.
• Portable jump starter: a lithium jump pack with sufficient peak amps is convenient and safer around sensitive electronics; keep it charged.

Investing in capable cables or a reputable jump pack reduces frustration and helps ensure a successful start when you need it most.

Common Mistakes to Avoid

These pitfalls can damage vehicles or cause injury; keeping them in mind ensures a safer jump-start.

• Reversing polarity (crossing + and –), which can damage electronics and batteries.
• Clamping to painted, oily, or corroded surfaces that prevent good contact.
• Jumping a visibly damaged, leaking, or frozen battery.
• Letting vehicles touch or letting clamps contact each other while connected.
• Ignoring the owner’s manual when jump posts or special procedures are specified.

Avoiding these errors helps prevent costly repairs and keeps the process straightforward and safe.

Summary

Use jumper cables by connecting red to positive on both vehicles, black to the donor’s negative, and the final black to a solid ground on the dead vehicle; start the donor, then the dead vehicle, and disconnect in reverse. Park safely, confirm 12V systems, use designated jump points on modern cars, and never jump a damaged battery. After starting, drive 20–30 minutes and test the battery and charging system to prevent repeat failures.

Do I remove positive or negative jumper cable first?

Disconnect the black, negative terminal first.
Then disconnect the red, positive terminal. Also wrap the red terminal with a cloth or cover it with a plastic cup to make sure it doesn’t touch the battery or any metal in the engine on accident.

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.

In what order should I jump start?

To jump-start a car, the jumper cable connection order is crucial for safety. Connect the red clamp to the positive terminal of the dead battery first, then the other red clamp to the positive terminal of the working (donor) battery. Next, connect the black clamp to the negative terminal of the working battery, and finally, connect the other black clamp to an unpainted metal surface on the dead car’s engine block away from the battery. Disconnect the cables in the reverse order.
 
Connecting the Jumper Cables

1. Red to Dead Battery: Connect the red (positive) clamp of the jumper cable to the positive terminal (+) of the car with the dead battery. 
2. Red to Donor Battery: Connect the other red (positive) clamp to the positive terminal (+) of the car with the working battery. 
3. Black to Donor Battery: Connect the black (negative) clamp to the negative terminal (-) of the car with the working battery. 
4. Black to Ground: Connect the final black (negative) clamp to an unpainted metal surface on the engine block of the car with the dead battery, away from the battery itself. 

Starting and Disconnecting

1. Start the Working Car: Start the engine of the vehicle with the good (donor) battery and let it run for a few minutes. 
2. Start the Dead Car: Try to start the engine of the car with the dead battery. 
3. Disconnect in Reverse Order: Once the dead car’s engine is running, disconnect the cables in the following reverse order: 
   • Black clamp from the engine block. 
   • Black clamp from the donor vehicle’s negative terminal. 
   • Red clamp from the donor vehicle’s positive terminal. 
   • Red clamp from the dead battery. 

This video demonstrates the proper way to jump start a car: 58sAAA Connect Video Hub | Auto Club GroupYouTube · Sep 23, 2024
Important Safety Tips

• Ensure both cars are turned off and the parking brakes are engaged. 
• Make sure the cars are close enough to reach but not touching. 
• Avoid contact between the positive and negative cables to prevent sparks. 
• If the dead car doesn’t start after a few tries, there may be a more serious issue requiring a mechanic. 

What is the correct order to attach jumper cables?

It goes like. This red to the dead. Red to the good black to the good. Then under the hood. Now let’s watch as Brian from Henderson Auto puts all of that into action.