When the Battery light comes on, some models will also set the BRAKE and/or other warning lights as well. This is by design. It’s just how the system is set-up to work. So if you have a Battery light on with other warning lights, concentrate on the Battery light first, as most times, resolving this will reset the others. When these dash lights are lit, this is a common sign of a fault in the Charging System. First- make sure to check your battery terminal connectors. Make sure they are tight, there is a solid connection from the cable to the connector end and that they are free of any corrosion. If there is corrosion build-up, some baking soda and water with a toothbrush make a good cleaning combination! If the cables and terminals check out ok, then there is a quick easy test for the charging system, with the use of a voltage meter. With the engine running, take a voltage reading at the battery terminals. If the voltage is not between 13.2-14.4v, or fluctuates in and out of this area, the Alternator will need to be replaced. If the Alternator passes this test, turn the engine off and wait 15min. Take another reading at the battery terminals, this time with the engine off. If the voltage is anything less than 12v, the battery may have a “bad cell” and is not accepting the alternator’s charge. If you do not have access to a voltage meter, most local “big chain” parts stores, like AutoZone or Advance Auto, will run these tests for Free right in their parking lot.