i beleve my alt is beginning to die. but last time mine went out, there was no buzzing. heres the scenerio...

under load OR at idle
below 2.5k buzzing clicks on for a second and all dummies come on. Voltage varies, but all under 12v.

above 2.5k lights go off. car runs fine. voltage at 12.5-13.8v

anybody know what the buzz is coming from?

ive got an S6 alt installed now, but im forcedto redo the wiring tomorow for my spare S4 alt to be dropped in. hopefully it all works.

 

based on those volt numbers it sounds like you alt. replace it. as for the buzzing not sure could be a voltage warning buzzer idk. our cars have wierd electrical issues. i would have things work when they felt like it in my car. not all the time....hmmm sounds like my honda to. haha