# Random alternator whine, wiring checks out, be prepared for alternator failure.



## Brian10962001 (Jul 11, 2009)

I just wanted to post this up, about a month ago I started getting a weird high pitched whine through my subwoofer. It would go away when the RCA's were pulled so I figured it was something to do with the grounding on my deck. I dialed the gains down, and got rid of it. I made the comment to my girlfriend that "the alternator might be going bad". Last night the whistle came back higher pitched than ever, by the time we got home my alt was doing 11 volts (stereo wasn't even playing for most of this trip). I've noticed this same thing in my Camaro, and my S10 truck. Both of them are running Auto Zone gangster alternators that need replaced about once a year (thank goodness for that lifetime warranty!). I have noticed that everytime before the alt lets go I'll start getting random noise in the signal. I swapped the Blazer's stock cs130D alt out for a Bosch AD244 (yeah don't ask, it was a JY pull, but at least it's an AD244 LOL) and the system is DEAD quiet again.


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

Brian10962001 said:


> I just wanted to post this up, about a month ago I started getting a weird high pitched whine through my subwoofer. It would go away when the RCA's were pulled so I figured it was something to do with the grounding on my deck. I dialed the gains down, and got rid of it. I made the comment to my girlfriend that "the alternator might be going bad". Last night the whistle came back higher pitched than ever, by the time we got home my alt was doing 11 volts (stereo wasn't even playing for most of this trip). I've noticed this same thing in my Camaro, and my S10 truck. Both of them are running Auto Zone gangster alternators that need replaced about once a year (thank goodness for that lifetime warranty!). I have noticed that everytime before the alt lets go I'll start getting random noise in the signal. I swapped the Blazer's stock cs130D alt out for a Bosch AD244 (yeah don't ask, it was a JY pull, but at least it's an AD244 LOL) and the system is DEAD qui*te* again.



Interesting and bizarre.. The car runs from the alt while the vehicle is running, but the battery usually acts as a "noise filter" of sorts in a lot of ways for the alt.. 

AFA the red above, it's quite DEAD qui*et* again..


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## Brian10962001 (Jul 11, 2009)

Correction made


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## WrenchGuy (Jun 10, 2007)

Diodes tend to fail and leak"noise" into the system.


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