The noise with the hvac I noticed on mine and I think it is electronic. I noticed it the other day when I had my radio off. the blend doors get moved electronically vs manual and that is what u hear, the motors running moving the doors. That is what I think anyway, the noise sounds electonic to me. As for other noises I get a hollow noise from when the key fob hits the dash, other than that I guess the regular GM noises, they are not to great to bother me tho