alternator/ voltmeter problem?
Last night i was driving around in my truck, and noticed the voltmeter was down at 9 instead of 12 and the batter light was on. that was at sitting at a stopsign, then about a mile down the road going 45 mph i saw the light go off and the gauge was sitting just a hair above 9 .when i went to start the truck this morning it started fine but the gauge still sat down in the red at 9. I'm only 17 and still learning so i don't know hardly anything about the charging system yet, so i need some help diagonsing the problem.