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07-24-2009, 07:55 AM #1
Alternator "buzzing" or "humming" when car is off, battery dies
Wondering if anybody has experienced this one.
Background: 1996 LT1, factory harness reworked by Speartech. I finally got my LT1 running and took the car for a spin around the block. Frickin' sweet!!
Instead of disconnecting the battery cables like I usually did durning the project build, I figured I'd leave everything connected. (this is how I will usually "store" the car for a week or two at a time) The following Saturday I put the keys in... nothing... dead battery.
Well, long story short, my faithful Optima red-top gave up the ghost after 6 hard years. So I bought a new one, installed it, everything worked great... until I came out to the garage the next morning. I heard a faint buzzing or humming... lifted the hood, and the sound is coming straight from the alternator. Sounds like the voltage regulator is buzzing. So I disconnected the plug that goes to the alternator... buzzing stops. Take my multimeter after it... sure enough, I'm getting voltage feeding from one of the wires to the alternator.
Is the alternator supposed to get voltage when the car is off? Is this a case of Speartech wiring it up to a constant hot versus a switched hot by accident? Yeah yeah, I'm going to call them, but I wanted to get educated before I go pointing fingers on who is to blame.
Oh, and the alt. checks out OK according to the factory troubleshooting guide.
The few, the proud, the crazy... the LT1 owners.
07-24-2009, 08:34 AM #2