Hey all, new to the board but spent some time reading and searching to try to answer a question that I have.



Just put a new alternator in the S4 and now when the car idles (860rpm) I hear a buzz that fades out and the entire idiot cluster and the Shift Up light comes on. Just like the lamp test right before you crank it up. Voltmeter shows a steady 13V even at idle... Battery may be on its way out but it holds a charge long enough to crank the car after a 10 hour rest.



Any ideas on what to check?





Oh, Car is stock except for a full 5lug swap, Vert LSD and lightweight flywheel and new clutch.

 

No ideas?



It's pissing me off... Amperage is good and I am stumped.

 

I would check your ground wires first.