What does the battery warning light do and why is it on?
The battery warning light comes on when the vehicle’s alternator isn’t charging properly. When this happens, the vehicle’s battery light comes on to warn you of the concern. Once this happens, you have a short amount of time to get to a repair facility. Make sure the engine doesn’t overheat when driving since some cars use the drive belt to turn the water pump and/or the cooling fan which is used to cool the engine as well as turn the alternator.
Common reasons for this to happen
- Faulty alternator
- Poor wiring at the alternator
- Blow fuse
- Broken drive belt
- Faulty voltage regulator
Can I drive with the battery warning light on? (Can I drive in Fail-Safe Mode?)
You can drive for a short time, but since the alternator isn’t charging you can only drive till the battery runs out of charge. After this, it will need to be charged, and the battery may take damage if you drive too far on just the battery’s voltage.
How do I fix a battery warning light?
- Check to make sure the drive belt is in tack; if it is broken and not turning the alternator, you will need to put a new belt on. Before putting the new belt on, make sure none of the pulleys in the system are locked up which could have caused the belt to break.
- If the belt is in tack and the alternator pulley is turning when the engine is on, use a voltmeter to check the battery voltage at idle. It should be roughly 14 volts; if it is 12 volts or less, the alternator is not charging.
- Check to make sure the alternator is plugged in and connected, if it is plugged in, it will need to be replaced.
Frequently Asked Questions
How far can I drive with the battery light on?
- It’s hard to say if the headlights or A/C are on it will decrease the distance. You shouldn’t drive it any further than necessary. Also, watch the engine coolant temperature to make sure the engine isn’t overheating.
Can the battery light cause my vehicle to drive irregularly?
- Yes absolutely. Your car needs electricity in order to function properly, and when this voltage drops below 12 volts the car can start to stumble, have a lack of acceleration, and lights can dim. Ultimately, the car will shut off and will have to be jumped off to start up again.
What does it mean if the battery light turns on and off?
- This could be an intermittent charging issue and can be a failed voltage regulator, which on newer cars is internal to the alternator.
At FIXD, our mission is to make car ownership as simple, easy, and affordable as possible. Our research team utilizes the latest automotive data and insights to create tools and resources that help drivers get peace of mind and save money over the life of their car.