How do I test to see if my battery or alternator is bad I

Hello, when the battery light comes on, it's in an indication of a concern with the charging system of the vehicle - the alternator, internal voltage regulator or the wiring to the alternator. This needs to be professionally tested; the system is not likely charging as needed an failures will likely result. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops