1992 Chevy Truck Aternator charging system

1992 CHEVROLET TRUCK
160,000 MILES • V8 • 4WD • AUTOMATIC
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TERRYGD
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I have put in a new lifetime warranty alternator, a new battery, less than 2 weeks ago. It works fine, right at 15 high 14, but when it gets hot(after about 20 minutes running) it goes clear down to 12 to 13. I have had the alternator tested and it test fine. I still think it is the alternator. HELP
Dec 7, 2008 at 8:40 PM
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BLUELIGHTNIN6
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Test the output terminal on the back of your alternator, it should be the same as at your battery. If it is more (engine running) or less (engine not running) by more then .2 of a volt check that wire for a burnt out fuseable link section or check underhood fuse box for a blown fuse (generally about 120amp fuse).

Also unplug the regulator plug from your alternator and with your ignition key in the "Run" position (engine stopped) you should have atleast 1 if not 2 terminals (depends on application) in the plug end coming from your vehicals wiring harness powered. If not powered, check fuses and these wires for breaks.
Dec 7, 2008 at 8:46 PM