Don't know why but this winter my rearview mirror LCD display slowly began to stop working. It would occasionally turn off and then on another day but now it is constantly off. It does however appear to dim still so I don't think the whole mirror is dead. Any ideas or similar problems for you guys? I've got a '99 Yukon with what appears to be the same mirror so I was hoping I could just swap them but I'm not completely sure what's involved with the mirror. (I don't dare mess with windshield stuff.) My truck is an '02 NBS. any ideas?