Connect red to the dead battery's positive terminal, red to the good battery's positive, black to the good battery's negative and the last black clamp to bare metal on the dead car. The battery light means the charging system is faulty, not necessarily the battery.
Key takeaways
- Last clamp goes on bare metal.
- Remove clamps in reverse order.
- A battery light means charging trouble.
Safe sequence
Turn both cars off. Red to dead positive, red to good positive, black to good negative, black to unpainted metal on the dead car. Start the good car, wait a few minutes, then start the dead car.
Why the last clamp goes on metal
It avoids sparks near the battery, which can vent flammable gas.
After the jump
Let the car run, then have the battery and charging system tested. Driving a short way does not fully recharge a battery.
The battery light
It shows the charging system is not producing the expected voltage, which may be the alternator, belt or wiring.
When to stop
If the light comes on while driving, reduce electrical loads and head for help. The car may stop when the battery drains.
Equipment and cables
Use cables with thick, clean clamps and enough length to reach without stretching. Cheap thin cables carry less current and heat up. A portable jump pack avoids the need for a second car and is useful for solo drivers. Keep it charged. Store cables where they will not rattle against sensitive parts in the trunk.
Why a jump is not a fix
A jump gets the engine running, but the battery is still discharged. If the alternator is weak, the car may stall again. If the battery is old, it may not recover. After any jump, have the battery and charging system tested within a day or two. Avoid long drives with a questionable battery, because a stall on the highway is a safety risk.
Need help in south Bakersfield?
Questions about auto electrical repair? Read our Auto Electrical Repair page, call (661) 599-9098 or request a time. Peña's Auto Electric, Smog & Repair, 303 Taft Hwy, Suite B, Bakersfield, CA 93307. Mon to Fri 9:30 AM to 5:30 PM, Sat 8 AM to 1 PM.
Frequently asked questions
Can I jump a hybrid?
Check your manual.
What if the car will not start after a jump?
The battery may be dead or the starter faulty.
Does the battery light mean replace the battery?
Not always.
How long should I let the car run?
Test it rather than guess.