Alternator problems? 98 Lincoln Navigator 4x4 Battery light comes on upon starting and stays on. Sometimes the battery light doesn't come on upon starting. When the battery light stayed on, I checked the voltage to the battery with my voltmeter. 11.4 volts When the battery light did not come on and remained off, I checked the voltage again. 13.4 volts My guess is the alternator is getting ready to go. I believe the battery is the original battery that came with the vehicle, so my question is whether the battery could somehow be causing the battery light to come on or whether it's just the alternator or both. My guess is the alternator due to the measured voltage I got when the light was both on and off.