Skip the auto shop - Our mechanics make house calls

Q: Battery light goes on and off.

asked by on

I have replaced battery and alternator. Battery light keeps on coming and off. It has been going on for 2 months.

My car has 119000 miles.
My car has an automatic transmission.

Hi there. The battery light continuing to come on after battery and alternator replacement can be caused by other issues. First thing is to have the charging system checked by a certified technician.

Even though the alternator has been replaced, it is possible to have installed a defective part. Other caused can be a loose or broken wire between the battery and alternator. Also, a failing belt tensioner can be at fault. If the belt tensioner is weak and not keeping proper tension on the serpentine belt, the belt can slip and not spin the alternator at the proper speed. If this happens, a low voltage can occur and cause the battery light to come on. If you need to have a precise diagnosis for the battery light, a qualified professional from YourMechanic can come to your car’s location to have this resolved.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: I suspect my egr system is clogged up possibly causing the knock senor code

Hey there, the EGR valve usually is located on the exhaust manifold. The EGR valve can become clogged over time leading to many different issues. In some cases, cleaning the EGR can fix the fault, but not always. When a...

Q: New battery, car still wont start even with jumper cables.

If the battery is new and fully charged, and you turn the key to the "start" position and you hear nothing that means that either the starter circuit supplying the starter motor (ignition switch, wiring, relay, fuse, etc.) has a...

Q: Steering/ front end vibration at high speeds

Hey there. I would recommend checking your intermediate shaft from the steering wheel to the rack and pinion. If the joint on your intermediate shaft has failed, this can cause the steering wheel to shake at certain speeds. If the...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.