03 Suburban with 215K. I just bought it; this noise came with the truck.


A look under the hood reveals recent alternator replacement.


Factory radio with Bose system. Bad whine that raises and lowers with RPM.


Something missing from the alternator? Bad alternator? Need a resistor inline somewhere?


What do you all think???


Thanks

 

Sounds like my Story sameO sameO took it to the best shop i know after asking 5 mechanics what they thought. We changed the tensioner and belt. still there . in the end the general consensus is that its the alternator and like yours mine was almost new obviously so im just keeping my eye on it and plan to replace it fairly soon. Hoping that will get rid of that high pitched whine.

 

You need to put in a ground loop isolayou have a ground that is not a good one but it's hard to find so putting in the isolator solves that problem put it behind your head unit/ radio

 

@zty116

That's if the whine comes from the speakers. If it's coming from the alt itself then it's bad.
Next time please think twice if it's really worth reviving 9 year old posts.

 

One, check your ground connections for the battery cable and make sure the battery cable to battery connections are clean and tight.

Two, if you have not load tested your battery, then you do not know if the battery is OK or not! You cannot simply go by battery voltage when the engine is off or running!

Two & a half, a properly charged battery that is in good condition should not see a significant voltage drop when you stop for a stop light and the bass kicks on unless you are running an amplifier in the kilowatt range. I run a 100 watt output ham radio in my vehicles and when I am stopped for a stop light and am talking on the radio, I do not see any significant voltage drop and the radio is pulling at least 20 amps.

Three, since you do not list the year, make, model, engine size of your vehicle, that hampers us assisting you.

Four, check all of the electrical connections to the battery, to grounds, to your audio equipment and make sure all of the connections are good, that the proper sized wire is used and that you are not using the cheap power tap type wiring connectors. Either solder the wires together or use decent crimp connectors and a decent crimping tool (and not a $1.99 special from Harbor Freight).