Q: My battery light came on its making a real bad whinning noise

Charging system output should be verified against factory specifications as the alternator may have failed which would account for both the noise and the battery warning light. It is also possible that the noise, and a charging failure, could be from a failed serpentine belt that is not properly driving the alternator. If the alternator tests bad, the battery should be carefully evaluated as well in a load test. Batteries are very important. If the battery only has a marginal pass on the load test you should just simply install a new battery to reduce diagnostic headaches. To have the alternator inspected, and replaced if necessary, please request an alternator inspection/replacement and the responding certified mechanic from YourMechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.