mite53

hey guys i have a question, i just bought a 2001 cl-s 3 weeks ago and i just noticed that when pushing the auto button on the rearview mirror the light does not turn on indicating that its in auto, i looked at the manual and it says that it should turn on, now before i go crying to a dealer(the warranty was transffered to my name) is there anything that i can do to troubleshoot it? maybe a fuse i can check or something like that because its not like my light is coming on and its just not dimming, the light is just not coming on at all. also will the warranty cover that?