The battery light on my 2004 E comes on intermittently. While driving, it may go off if RPM are above 3,000. While idling, it may or may not come on. I finally caught the light on while idling at home and checked the battery voltage: about 12.5. When the light is off the voltage is above 14. Last time I checked the cold battery it was 12.6. This has been going on for weeks so the alternator must be topping off the battery whenever the light is off, but I feel like I'm asking for trouble driving to work everyday. Loose connection somewhere? Bad voltage regulator? I replaced the ECM a few years ago, and the alternator maybe 1 or 2 years ago.