I own a 2004 chevy malibu classic and upon reaching 20mph a whining noise starts and changes in pitch as i increase in speed.. also occasionally my dashboard lights will dim in and out.. any advice on this matter will be greatly appreciated...
Could it actually be the alternator? Those symptoms sound a bit consistent, with the sound coming from that area and the lights dimming. If you have an Autozone nearby they do free alternator testing and could at least tell you if there are issues with it's output.
Another good suggestion. I misread the car- it's a 2004 Classic (aka - 97-03 'bu style). Our 97 not only had the alternator replaced twice, but the pulleys needed replaced later. I can't remember for sure, but the noise described here might've been one of the symptoms that caused me to take it in when the service department discovered them going bad.
You are lucky you can tell what's whining. I didn't find my idler pulley whining until it was too late, as my supercharger (Grand Prix) also whines really loudly. Shredded both belts and the plastic pulley was no more-only a bearing left.