Jump-start a dead battery safely
Jumper cables are simple until you hook them wrong. Do it right and you'll avoid sparks, ruined electronics, and a tow you didn't need.
What you'll learn
- The correct red-then-black clamp order (and why it matters)
- Why the last clamp goes on a bare metal point, not the dead battery
- When a jump-pack beats a cable-to-cable jump
- Signs that the alternator is bad and a jump will not fix the car
Step by step
- Pull the donor car close enough for the cables to reach. Both cars OFF.
- Clamp RED to POSITIVE (+) on the dead battery.
- Clamp RED to POSITIVE (+) on the donor battery.
- Clamp BLACK to NEGATIVE (−) on the donor battery.
- Clamp BLACK to bare metal on the dead car's engine block (not the battery).
- Start the donor. Wait 2 minutes. Start the dead car. Let run 10 minutes before driving.
If the car cranks weakly or dies again within an hour, the alternator or battery has failed. A second jump will not help, so call for a tow to a shop. Chicago batteries take a beating from both ends of the year: the National Weather Service records 121.3 nights a year at or below freezing at O'Hare and 6.5 at or below zero, and a hot, humid July does its own damage. If your battery is more than three years old and it has died once this winter, replace it before it strands you on a night when every operator in the metro is already committed.
Rather have a pro handle it?
Towing and roadside service across the Chicago metro. One local line, answered 24/7.
Keep learning.
Change a flat tire on the side of the road
The difference between a 20-minute shoulder stop and an hour on the phone with a tow company is knowing where the spare and jack live before you need them.
What to do if you slide on ice or hit a flooded viaduct
Chicago winters glaze bridges and ramps before flat streets, and a heavy rain fills a viaduct underpass faster than it looks. First step: stop making it worse.
Prepare your vehicle for a tow
A few minutes of prep before the tow truck arrives saves time, avoids damage, and makes the whole call go faster.