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Q: Battery light goes on and off.

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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.

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