Mechanics

FLUCTUATING VOLTAGE

2000 GMC Sierra • 6 cylinder 2WD •

What causes the voltage to fluctuate on the battery and lights flash on my 2002 GMC Sierra
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Gmcbluz
May 21, 2011.




Test the charging system. Battery has a full charge and all connections, clean and tight?


JDL
May 21, 2011.
Yes, first thing I checked
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Tiny
Gmcbluz
May 21, 2011.
I did look at your TSBs, one of them said, "this is normal unless there is a proven fault".

I know that doesn't help much, did it just start doing this or has it been doing this all along?

With engine running, warm idle, all electrical loads turned on, what is the voltage reading across battery posts as compared to alternator bat terminal?

Are you saying, your headlamps go out?


JDL
May 21, 2011.

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