With both cars off, connect the cables in this order: 1. red to the dead battery’s +, 2. red to the good battery’s +, 3. black to the good battery’s −, 4. black to bare metal on the dead car’s engine, away from its battery. Start the good car, let it run a little faster than idle, then start the dead car. Take the cables off in reverse order (Honda).
Before you start
- Check your owner’s manual. Ford points owners to the jump-starting section of their own vehicle’s manual; Honda’s shows the exact ground point.
- Keep sparks and flames away. A battery gives off explosive hydrogen gas, and a spark can make it explode (Honda).
- Use a 12-volt source only: another car’s 12-volt battery or a 12-volt booster (Honda).
- Turn everything off: lights, audio and other electrical devices, and the engine. Then open the hood (Honda).
How to jump-start a car, step by step
- Red clamp on the dead battery’s positive (+) terminal. Open the terminal cover if there is one (Honda).
- Other red clamp on the good battery’s positive (+) terminal.
- Black clamp on the good battery’s negative (−) terminal.
- Other black clamp on the ground point of the dead car, a bolt or bare metal on the engine that your manual shows. Honda uses a stud bolt on the engine and says not to connect this cable to any other part. Keeping this last connection away from the battery keeps any spark away from its gas.
- Start the good car and raise its engine speed slightly (Honda).
- Start the dead car. If it turns over slowly, check that every clamp has good metal-to-metal contact (Honda).
- Remove the cables in reverse order: the black clamp from the ground point, then from the good battery’s −, then the red clamp from your battery’s +, then from the good battery’s + (Honda).
Clamp the cables on firmly so engine vibration can’t shake them off, and don’t let the clamps touch each other while the cables are connected (Honda).
After it starts
A battery that went flat once may do it again. Honda says to have the car inspected by a service station or dealer after a jump-start, and Ford suggests having the battery tested. Batteries also lose power in cold weather, which can stop an engine starting (Honda).
Booster packs, chargers and electric cars
- Portable booster or charger: use a 12-volt unit. If you boost with a battery charger, Honda says to choose a charging voltage below 15 volts.
- Electric vehicles: on the Ford Mustang Mach-E and F-150 Lightning, the 12-volt battery has to be given a charge to open the door and hood before you can attach cables (Ford). Follow the manual for any hybrid or electric car.
Questions people ask
Which jumper cable goes on first?
The red one, on the dead battery’s positive (+) terminal. Then red to the good battery’s +, black to the good battery’s −, and black to a ground point on the dead car’s engine (Honda).
Why does the last black clamp go on the engine, not the battery?
The last connection can spark. Making it on bare metal away from the battery keeps the spark away from the explosive gas a battery gives off (Honda).
In what order do you remove jumper cables?
The reverse of how they went on: black from the engine ground, black from the good battery, red from your battery, red from the good battery (Honda).
Why won’t my car start after a jump?
First check the clamps: a slow crank often means poor contact (Honda). If it still won’t start, the battery may be beyond recovering or the fault may be elsewhere; have it checked.
What does the battery light mean?
A problem with the charging system: the battery isn’t being charged. See the battery light.
Sources
- Honda, 2023 Integra Owner’s Manual: If the Battery Is Dead (Jump Starting Procedure) and Checking the Battery: the connection and removal order; the ground stud; 12-volt boosters; chargers below 15 volts; explosive gas and sparks; cold weather; inspection afterward.
- Ford, How do I jump start the battery in my vehicle?: instructions in each owner’s manual; Mustang Mach-E and F-150 Lightning need a charge to open the door and hood; battery testing afterward.