PullBattery light on or charging problems
General info, not professional advice. These are common causes that apply to most cars, not a diagnosis of yours. If you are unsure or a problem affects brakes, steering, airbags or fuel, see a qualified mechanic.
Likely causes (most common first)
- Failing alternator
The battery light is on while driving, lights dim, and the battery keeps going dead.
🔎 Find a used alternator - Worn or loose serpentine belt
Squealing, and the alternator isn't turning properly.
🔎 Find a used serpentine belt - Old battery that won't hold a charge
Batteries often last around 3 to 5 years.
🔎 Find a used battery - Bad cable or ground connection
Corrosion or a loose ground strap.
🔎 Find a used battery cable
Quick safe checks
- With the engine running, a voltmeter across the battery usually reads about 13.5 to 14.8 V. Engine off, a healthy battery is about 12.4 to 12.7 V.
- Look at the serpentine belt for cracks, glazing or looseness, with the engine off.
- Many auto parts stores test batteries and alternators for free.
Safety first
- ⚠️ Car batteries can spark and give off explosive gas. Wear eye protection, take off metal jewelry, and disconnect the negative (−) cable first.
- ⚠️ Keep hands, hair and loose clothing away from belts and the cooling fan. The fan can turn on even with the engine off.
When to see a pro
The battery light stays on after a new battery and belt check, or you see a burning smell or melted wiring.