Originally Posted by mn__30
Im 100% sure that your alternator is bad. Replace it!!!
Exactly. Mine did the same shit when it went out.
Get a voltmeter and test out your battery charge, especially with a heavily load on the battery - high beams on, full fan speed, radio, etc. if your battery voltage is decreasing, it's time for a new alternator. Mine went at 140k and made a loud whirring noise before it did.