Hey. My immaculate condition Camry XLI's battery light went on while I was driving this morning. What can this be?

 

The battery light is like the charge light on older cars. It indicates there is a problem with the cars 12v electrical charging system.

If the light is on, the charging system is not working properly. This means the cars electrical system is now operating solely off the battery and not being recharged. And sooner or later the battery will go dead.

If you have a volt meter, check battery voltage engine off. Then check voltage at battery engine running at approx 2500 rpm and check if voltage is between say 13.1 and 14v, more or less. If battery voltage is the same or less then battery voltage engine off the charging system is not working.

Problems can be failed alternator (typically worn out brushes which can be replaced), bad battery cable connections, bad ground connection of battery to chassis, bad electrical harness connection at alt, loose alternator drive belt.

When checking the system, don't operate the engine with battery disconnected or this can cause damage to the alt.

If you know someone handy with tools and understands basic auto electrical systems have them check the alternator brushes. This can be done with the alt on the car. If worn out they can be replaced cheaply enough. This route is better then replacing the alt with a 'rebuilt" unit.