My car still starts fine but when I turn off the car (just the motor . . the key is still in and "on") I noticed the headlights dim to almost off. It's and older car and the headlights don't turn off automatically.
The battery is over 4 years old and in Arizona "they say" batteries only last 2 or 3 years. Should I go and get a new battery or wait until the car won't start? Can I test the battery with a simple tester to see if it's still delivering 12 volts?