Why does my Battery charge lamp glowing dim when engine running?

Answer 1

Meaning of a Glowing Battery Charge Indicator Lamp while Engine is RunningAlthough there could be several causes, and without doing a "hands on troubleshooting" of your vehicle, no one here can tell you the specific cause.

However, a glowing Charging Circuit Warning Light [sometimes called an "Idiot Light"] usually indicates that the voltage in the charging circuit is NOT ENOUGH to charge the battery.

The cause could include one or more of the following problems [and this list is only the things I can recall at the moment, and there are probably others]:

• IF it occurs while the engine is idling, it could be nothing more than the idle speed [Rpm] being set too low,
• If it occurs at all engine speeds, then it's possible that the belt driving the alternator and/or generator [if so equipped] is not adjusted properly and is slipping,
• A poor or open ground connection anywhere in the charging system could be preventing the proper flow of current,
• The voltage regulator [sometimes inside the alternator, or sometimes mounted outside the alternator in the engine compartment] could be defective,
• And there are surely other possible causes that I can't recall at the moment.

EDIT: You really need to check battery voltage with headlights on and at engine at fast idle. If it is 13.8 to 14.4 volts; it's either the indicator or a bad regulator giving a false signal. A battery with a bad or reversing cell can constantly draw current, giving a "gen" light, too. Although you need to get this checked out; if there is no problem; bear in mind that some cars have"dim" indicators at times. My Chevy's "Choke/Oil" lamp will come on, dimly, at warm-up. Sometimes it's normal.