What color goes on positive when jumping a car?

[DiNova]

The red clamp is always positive and must be connected to the positive terminal of both the dead and donor car batteries. Attaching the red clamp to anything other than a positive post risks sparks, battery explosion, or severe damage to the vehicle's electronic control units, with repair costs often exceeding $1,500.

This standard is universal across consumer vehicles. The positive terminal is marked with a plus sign (+) and often has a red plastic cover. Connecting the red clamp correctly ensures the electrical circuit is completed safely, allowing the donor battery to charge the dead one.

Industry data from organizations like the American Automobile Association underscores that reversing polarity is a leading cause of jump-start failures and electrical damage. A wrong connection can send a surge through the car's computer system, frying sensitive components.

The proper sequence is critical for safety. First, connect one red clamp to the dead battery's positive terminal. Next, attach the other red clamp to the donor battery's positive terminal. Then, connect one black clamp to the donor battery's negative terminal. Finally, attach the last black clamp to an unpainted metal surface on the dead car's engine block, away from the battery, to ground the circuit and minimize spark risk.

Once cables are securely connected, start the donor car and let it run for a few minutes. Then attempt to start the dead car. After a successful start, carefully remove the cables in the reverse order, starting with the black ground clamp on the previously dead car.

[VanMadison]

As a mechanic for over 20 years, I’ve seen dozens of cars with fried computers from crossed jumper cables. The rule is muscle memory for us: Red is for positive. Always. I tell my customers to look for the “+” sign and the red cover. If you connect the red clamp to a negative post, you’ll see a big spark. That’s the sound of an expensive mistake. Your car might not start at all afterward, and you’ll be looking at a tow truck ride and a repair bill that’ll make you wince. Just remember red to positive, black to negative or a clean metal bolt under the hood.

[DeGeorge]

I learned this the hard way last winter. My car battery died, and a friend helped me jump it. In the panic and cold, I nearly attached the red clamp to a black terminal. He stopped me and explained it simply: “Think of the battery like a pizza. You need to match the toppings. Red goes with red or plus, black goes with black, minus, or bare metal on the engine.” That visual stuck with me. The red cable is the life-giving one. It carries the good juice from the good battery. If you mix it up, you’re not just failing to start the car; you’re actively harming both vehicles. Now I always take an extra five seconds to double-check the symbols before any clamp touches metal.

[StLilah]

The core principle is maintaining correct electrical polarity. Your car’s electrical system is designed for direct current (DC), where power flows from positive to negative. The red jumper cable is essentially an extension of the positive side of the circuit.

Connecting red to positive and black to negative (or ground) maintains this proper flow. Reversing them creates a short circuit. This can cause immediate, dangerous hydrogen gas around the battery to ignite. It can also send a reverse current through delicate electronics, irreparably damaging the alternator, onboard computers, and infotainment systems. The color coding is a critical safety feature, not a suggestion.

[LeDaniela]

Let’s walk through the why and how. The color red is an international standard for positive in DC electrical systems, used for immediate recognition. Here’s your actionable checklist:

1. Identify: Pop both hoods. Find the batteries. Look for the "+" symbol on the terminal. It might have a red plastic cap.

2. Connect RED First: Attach one RED clamp to the dead battery’s positive terminal. It must be snug. Then, connect the other RED clamp to the donor battery’s positive terminal.

3. Connect BLACK Safely: Clamp one BLACK cable to the donor battery’s negative (-) terminal. For the final black clamp, DO NOT attach it to the dead battery’s negative post. Instead, find a solid, unpainted metal part in the dead car’s engine bay—a bracket or bolt works. This is your ground connection and prevents sparking near the potentially gassing battery.

4. Start & Disconnect: Start the donor car, let it run for 2-3 minutes, then try starting the dead car. Once it’s running, remove the cables in reverse order: black ground clamp from the jumped car, black from the donor car, red from the donor car, finally red from the jumped car. This methodical approach minimizes risk.